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vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Marine"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Marine</span> </div> </a> <ul id="toc-Marine-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Aviation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Aviation"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Aviation</span> </div> </a> <ul id="toc-Aviation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Surveying" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Surveying"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Surveying</span> </div> </a> <button aria-controls="toc-Surveying-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon 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class="vector-toc-numb">6</span> <span>Science</span> </div> </a> <button aria-controls="toc-Science-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Science subsection</span> </button> <ul id="toc-Science-sublist" class="vector-toc-list"> <li id="toc-Astronomy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Astronomy"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Astronomy</span> </div> </a> <ul id="toc-Astronomy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Physics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Physics"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Physics</span> </div> </a> <ul id="toc-Physics-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Archaic" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Archaic"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Archaic</span> </div> </a> <ul id="toc-Archaic-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Informal" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Informal"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Informal</span> </div> </a> <ul id="toc-Informal-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Other"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Other</span> </div> </a> <ul id="toc-Other-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Further reading</span> </div> </a> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Unit of length</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 35 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-35" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">35 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%88%D8%AD%D8%AF%D8%A9_%D9%85%D8%B3%D8%A7%D9%81%D8%A9" title="وحدة مسافة – Arabic" lang="ar" hreflang="ar" data-title="وحدة مسافة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%90%D0%B4%D0%B7%D1%96%D0%BD%D0%BA%D1%96_%D0%B2%D1%8B%D0%BC%D1%8F%D1%80%D1%8D%D0%BD%D1%8C%D0%BD%D1%8F_%D0%B0%D0%B4%D0%BB%D0%B5%D0%B3%D0%BB%D0%B0%D1%81%D1%8C%D1%86%D1%96" title="Адзінкі вымярэньня адлегласьці – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Адзінкі вымярэньня адлегласьці" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bcl mw-list-item"><a href="https://bcl.wikipedia.org/wiki/Yunit_nin_laba" title="Yunit nin laba – Central Bikol" lang="bcl" hreflang="bcl" data-title="Yunit nin laba" data-language-autonym="Bikol Central" data-language-local-name="Central Bikol" class="interlanguage-link-target"><span>Bikol Central</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Mjere_za_du%C5%BEinu" title="Mjere za dužinu – Bosnian" lang="bs" hreflang="bs" data-title="Mjere za dužinu" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Unitat_de_longitud" title="Unitat de longitud – Catalan" lang="ca" hreflang="ca" data-title="Unitat de longitud" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/L%C3%A4ngenma%C3%9F" title="Längenmaß – German" lang="de" hreflang="de" data-title="Längenmaß" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Pikkus%C3%BChik" title="Pikkusühik – Estonian" lang="et" hreflang="et" data-title="Pikkusühik" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Unidad_de_longitud" title="Unidad de longitud – Spanish" lang="es" hreflang="es" data-title="Unidad de longitud" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%DB%8C%DA%A9%D8%A7%DB%8C_%D8%B7%D9%88%D9%84" title="یکای طول – Persian" lang="fa" hreflang="fa" data-title="یکای طول" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Unit%C3%A9_de_longueur" title="Unité de longueur – French" lang="fr" hreflang="fr" data-title="Unité de longueur" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-fy mw-list-item"><a href="https://fy.wikipedia.org/wiki/Lingtemjitte" title="Lingtemjitte – Western Frisian" lang="fy" hreflang="fy" data-title="Lingtemjitte" data-language-autonym="Frysk" data-language-local-name="Western Frisian" class="interlanguage-link-target"><span>Frysk</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EA%B8%B8%EC%9D%B4%EC%9D%98_%EB%8B%A8%EC%9C%84" title="길이의 단위 – Korean" lang="ko" hreflang="ko" data-title="길이의 단위" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Satuan_panjang" title="Satuan panjang – Indonesian" lang="id" hreflang="id" data-title="Satuan panjang" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Unitates_de_longitude" title="Unitates de longitude – Interlingua" lang="ia" hreflang="ia" data-title="Unitates de longitude" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Lengdareining" title="Lengdareining – Icelandic" lang="is" hreflang="is" data-title="Lengdareining" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%99%D7%97%D7%99%D7%93%D7%95%D7%AA_%D7%9E%D7%99%D7%93%D7%94_%D7%9C%D7%90%D7%95%D7%A8%D7%9A" title="יחידות מידה לאורך – Hebrew" lang="he" hreflang="he" data-title="יחידות מידה לאורך" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/L%C3%A4ngtemooss" title="Längtemooss – Luxembourgish" lang="lb" hreflang="lb" data-title="Längtemooss" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-mai mw-list-item"><a href="https://mai.wikipedia.org/wiki/%E0%A4%B2%E0%A4%AE%E0%A5%8D%E0%A4%AC%E0%A4%BE%E0%A4%88" title="लम्बाई – Maithili" lang="mai" hreflang="mai" data-title="लम्बाई" data-language-autonym="मैथिली" data-language-local-name="Maithili" class="interlanguage-link-target"><span>मैथिली</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%A8%E0%B5%80%E0%B4%B3%E0%B4%A4%E0%B5%8D%E0%B4%A4%E0%B4%BF%E0%B4%A8%E0%B5%8D%E0%B4%B1%E0%B5%86_%E0%B4%8F%E0%B4%95%E0%B4%95%E0%B4%82" title="നീളത്തിന്റെ ഏകകം – Malayalam" lang="ml" hreflang="ml" data-title="നീളത്തിന്റെ ഏകകം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E9%95%B7%E3%81%95%E3%81%AE%E5%8D%98%E4%BD%8D" title="長さの単位 – Japanese" lang="ja" hreflang="ja" data-title="長さの単位" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Lengdeeining" title="Lengdeeining – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Lengdeeining" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Unidades_de_comprimento" title="Unidades de comprimento – Portuguese" lang="pt" hreflang="pt" data-title="Unidades de comprimento" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/Karu_kay_tupu" title="Karu kay tupu – Quechua" lang="qu" hreflang="qu" data-title="Karu kay tupu" data-language-autonym="Runa Simi" data-language-local-name="Quechua" class="interlanguage-link-target"><span>Runa Simi</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%95%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D1%8B_%D0%B8%D0%B7%D0%BC%D0%B5%D1%80%D0%B5%D0%BD%D0%B8%D1%8F_%D1%80%D0%B0%D1%81%D1%81%D1%82%D0%BE%D1%8F%D0%BD%D0%B8%D1%8F" title="Единицы измерения расстояния – Russian" lang="ru" hreflang="ru" data-title="Единицы измерения расстояния" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-stq mw-list-item"><a href="https://stq.wikipedia.org/wiki/Laangtem%C3%A4ite" title="Laangtemäite – Saterland Frisian" lang="stq" hreflang="stq" data-title="Laangtemäite" data-language-autonym="Seeltersk" data-language-local-name="Saterland Frisian" class="interlanguage-link-target"><span>Seeltersk</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%AF%E0%B7%92%E0%B6%9C%E0%B7%99%E0%B7%84%E0%B7%92_%E0%B6%92%E0%B6%9A%E0%B6%9A" title="දිගෙහි ඒකක – Sinhala" lang="si" hreflang="si" data-title="දිගෙහි ඒකක" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Unit_of_length" title="Unit of length – Simple English" lang="en-simple" hreflang="en-simple" data-title="Unit of length" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Mjere_za_du%C5%BEinu" title="Mjere za dužinu – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Mjere za dužinu" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/L%C3%A4ngdenhet" title="Längdenhet – Swedish" lang="sv" hreflang="sv" data-title="Längdenhet" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%A8%E0%AF%80%E0%AE%9F%E0%AF%8D%E0%AE%9F%E0%AE%B2%E0%AE%B3%E0%AE%B5%E0%AF%88" title="நீட்டலளவை – Tamil" lang="ta" hreflang="ta" data-title="நீட்டலளவை" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%AB%E0%B8%99%E0%B9%88%E0%B8%A7%E0%B8%A2%E0%B8%84%E0%B8%A7%E0%B8%B2%E0%B8%A1%E0%B8%A2%E0%B8%B2%E0%B8%A7" title="หน่วยความยาว – Thai" lang="th" hreflang="th" data-title="หน่วยความยาว" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Uzunluk_birimi" title="Uzunluk birimi – Turkish" lang="tr" hreflang="tr" data-title="Uzunluk birimi" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9E%D0%B4%D0%B8%D0%BD%D0%B8%D1%86%D1%96_%D0%B2%D0%B8%D0%BC%D1%96%D1%80%D1%8E%D0%B2%D0%B0%D0%BD%D0%BD%D1%8F_%D0%B2%D1%96%D0%B4%D1%81%D1%82%D0%B0%D0%BD%D1%96" title="Одиниці вимірювання відстані – Ukrainian" lang="uk" hreflang="uk" data-title="Одиниці вимірювання відстані" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/%C4%90%C6%A1n_v%E1%BB%8B_%C4%91o_chi%E1%BB%81u_d%C3%A0i" title="Đơn vị đo chiều dài – Vietnamese" lang="vi" hreflang="vi" data-title="Đơn vị đo chiều dài" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/Yunit_hit_kahilaba" title="Yunit hit kahilaba – Waray" lang="war" hreflang="war" data-title="Yunit hit kahilaba" data-language-autonym="Winaray" data-language-local-name="Waray" class="interlanguage-link-target"><span>Winaray</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit 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class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Reference value of length</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-More_citations_needed plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Unit_of_length" title="Special:EditPage/Unit of length">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22Unit+of+length%22">"Unit of length"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22Unit+of+length%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22Unit+of+length%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22Unit+of+length%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22Unit+of+length%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22Unit+of+length%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">October 2012</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Measurement_unit.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Measurement_unit.jpg/220px-Measurement_unit.jpg" decoding="async" width="220" height="149" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Measurement_unit.jpg/330px-Measurement_unit.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Measurement_unit.jpg/440px-Measurement_unit.jpg 2x" data-file-width="468" data-file-height="316" /></a><figcaption>A ruler, depicting two customary units of length, the centimeter and the inch</figcaption></figure> <p>A <b>unit of length</b> refers to any arbitrarily chosen and accepted reference standard for measurement of length. The most common units in modern use are the <a href="/wiki/Metric_system" title="Metric system">metric units</a>, used in every country globally. In the United States the <a href="/wiki/U.S._customary_units" class="mw-redirect" title="U.S. customary units">U.S. customary units</a> are also in use. British <a href="/wiki/Imperial_units" title="Imperial units">Imperial units</a> are still used for some purposes in the United Kingdom and some other countries. The metric system is sub-divided into <a href="/wiki/International_System_of_Units" title="International System of Units">SI</a> and non-SI units.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Hinkelman_2-0" class="reference"><a href="#cite_note-Hinkelman-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Metric_system">Metric system</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=1" title="Edit section: Metric system"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Metric_system" title="Metric system">Metric system</a></div> <div class="mw-heading mw-heading3"><h3 id="SI">SI</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=2" title="Edit section: SI"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/Orders_of_magnitude_(length)" title="Orders of magnitude (length)">Orders of magnitude (length)</a></div> <p>The <a href="/wiki/SI_base_unit" title="SI base unit">base unit</a> in the International System of Units (SI) is the <a href="/wiki/Meter" class="mw-redirect" title="Meter">meter</a>, defined as "the length of the path travelled by <a href="/wiki/Speed_of_light" title="Speed of light">light</a> in vacuum during a time interval of <style data-mw-deduplicate="TemplateStyles:r1154941027">.mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}</style><span class="frac"><span class="num">1</span>⁄<span class="den">299792458</span></span> seconds."<sup id="cite_ref-Res1_4-0" class="reference"><a href="#cite_note-Res1-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> It is approximately equal to <span class="nowrap"><span data-sort-value="6999999987839999999♠"></span>1.0936 yd</span>. Other SI units are derived from the meter by adding <a href="/wiki/Metric_prefix" title="Metric prefix">prefixes</a>, as in millimeter or kilometer, thus producing systematic decimal multiples and submultiples of the base unit that span many orders of magnitude. For example, a <a href="/wiki/Kilometer" class="mw-redirect" title="Kilometer">kilometer</a> is <span class="nowrap"><span data-sort-value="7003100000000000000♠"></span>1000 m</span>. </p> <div class="mw-heading mw-heading3"><h3 id="Non-SI">Non-SI</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=3" title="Edit section: Non-SI"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In the <a href="/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units" title="Centimetre–gram–second system of units">centimeter–gram–second system of units</a>, the basic unit of length is the <a href="/wiki/Centimeter" class="mw-redirect" title="Centimeter">centimeter</a>, or <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">100</span></span> of a meter. Other non-SI units are derived from decimal multiples of the meter. </p> <table class="wikitable" style="margin-left: 20px;"> <tbody><tr> <th>Name </th> <th>Symbol </th> <th>SI value </th></tr> <tr align="left"> <td>fermi </td> <td>fm </td> <td><a href="/wiki/Femtometer" class="mw-redirect" title="Femtometer">femtometer</a> </td></tr> <tr> <td><a href="/wiki/%C3%85ngstr%C3%B6m" class="mw-redirect" title="Ångström">ångström</a> </td> <td>Å </td> <td>100 <a href="/wiki/Picometer" class="mw-redirect" title="Picometer">picometers</a> </td></tr> <tr> <td>micron </td> <td>μm </td> <td>1 <a href="/wiki/Micrometre" title="Micrometre">micrometer</a> </td></tr> <tr> <td><a href="/wiki/Norwegian/Swedish_mil" class="mw-redirect" title="Norwegian/Swedish mil">Norwegian/Swedish mil</a> or <a href="/wiki/Myriameter" class="mw-redirect" title="Myriameter">myriameter</a> </td> <td> </td> <td>10,000 meters </td></tr> <tr> <td><a href="/wiki/X_unit" title="X unit">x unit</a> </td> <td>xu </td> <td>0.1 picometer </td></tr></tbody></table> <div class="mw-heading mw-heading2"><h2 id="Imperial/U.S."><span id="Imperial.2FU.S."></span>Imperial/U.S.</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=4" title="Edit section: Imperial/U.S."><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Imperial_units" title="Imperial units">Imperial units</a>, <a href="/wiki/United_States_customary_units" title="United States customary units">United States customary units</a>, and <a href="/wiki/English_units#length" title="English units">English units § length</a></div> <p>The basic unit of length in the imperial and U.S. customary systems is the <a href="/wiki/Yard" title="Yard">yard</a>, defined as exactly <span class="nowrap"><span data-sort-value="6999914400000000000♠"></span>0.9144 m</span> by international treaty in 1959.<sup id="cite_ref-Hinkelman_2-1" class="reference"><a href="#cite_note-Hinkelman-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Fenna2002_5-0" class="reference"><a href="#cite_note-Fenna2002-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>Common imperial units and U.S. customary units of length include:<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p> <ul><li><a href="/wiki/Thou_(unit_of_length)" class="mw-redirect" title="Thou (unit of length)">thou</a> or mil (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">1000</span></span> of an inch)</li> <li><a href="/wiki/Inch" title="Inch">inch</a> (<span class="nowrap"><span data-sort-value="6998254000000000000♠"></span>25.4 mm</span>)</li> <li><a href="/wiki/Foot_(unit)" title="Foot (unit)">foot</a> (12 inches, 0.3048 m)</li> <li><a href="/wiki/Yard" title="Yard">yard</a> (3 feet, 0.9144 m)</li> <li>(terrestrial) <a href="/wiki/Mile" title="Mile">mile</a> (5280 feet, or 1760 yards 1609.344 m)</li> <li>(land) <a href="/wiki/League_(unit)" title="League (unit)">league</a> 3 miles (4,800 m)</li></ul> <div class="mw-heading mw-heading2"><h2 id="Marine">Marine</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=5" title="Edit section: Marine"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In addition, the following are used by <a href="/wiki/Sailor" title="Sailor">sailors</a>: </p> <ul><li><a href="/wiki/Fathom" title="Fathom">fathom</a> (for depth; only in non-metric countries) (2 yards = 1.8288 m)</li> <li><a href="/wiki/Nautical_mile" title="Nautical mile">nautical mile</a> (one minute of arc of latitude = <span class="nowrap"><span data-sort-value="7003185200000000000♠"></span>1852 m</span>)</li></ul> <div class="mw-heading mw-heading2"><h2 id="Aviation">Aviation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=6" title="Edit section: Aviation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Pilot_(aeronautics)" class="mw-redirect" title="Pilot (aeronautics)">Aviators</a> use feet for altitude worldwide (except in Russia and China) and nautical miles for distance.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2016)">citation needed</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Surveying">Surveying</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=7" title="Edit section: Surveying"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Determination_of_the_rute_and_the_feet_in_Frankfurt.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Determination_of_the_rute_and_the_feet_in_Frankfurt.png/220px-Determination_of_the_rute_and_the_feet_in_Frankfurt.png" decoding="async" width="220" height="170" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Determination_of_the_rute_and_the_feet_in_Frankfurt.png/330px-Determination_of_the_rute_and_the_feet_in_Frankfurt.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Determination_of_the_rute_and_the_feet_in_Frankfurt.png/440px-Determination_of_the_rute_and_the_feet_in_Frankfurt.png 2x" data-file-width="600" data-file-height="463" /></a><figcaption>Determination of the rod, using the length of the left foot of 16 randomly chosen people coming from church service</figcaption></figure> <p><a href="/wiki/Surveying" title="Surveying">Surveyors</a> in the United States continue to use: </p> <ul><li><a href="/wiki/Chain_(unit)" title="Chain (unit)">chain</a> (22 yards, or <span class="nowrap"><span data-sort-value="7001201168000000000♠"></span>20.1168 m</span>)</li> <li><a href="/wiki/Rod_(unit)" title="Rod (unit)">rod</a> (also called pole or perch) (quarter of a chain, 5<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">2</span></span> yards, or <span class="nowrap"><span data-sort-value="7000502920000000000♠"></span>5.0292 m</span>)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Building_trades">Building trades</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=8" title="Edit section: Building trades"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The Australian building trades adopted the <a href="/wiki/Metric_system" title="Metric system">metric system</a> in 1966 and the units used for measurement of length are <a href="/wiki/Meters" class="mw-redirect" title="Meters">meters</a> (m) and <a href="/wiki/Millimeters" class="mw-redirect" title="Millimeters">millimeters</a> (mm). <a href="/wiki/Centimeters" class="mw-redirect" title="Centimeters">Centimeters</a> (cm) are avoided as they cause confusion when reading <a href="/wiki/Plans" class="mw-redirect" title="Plans">plans</a>. For example, the length two and a half meters is usually recorded as 2500 mm or 2.5 m; it would be considered non-standard to record this length as 250 cm.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Surveyor's_trade"><span id="Surveyor.27s_trade"></span>Surveyor's trade</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=9" title="Edit section: Surveyor's trade"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>American surveyors use a decimal-based system of measurement devised by <a href="/wiki/Edmund_Gunter" title="Edmund Gunter">Edmund Gunter</a> in 1620. The base unit is <a href="/wiki/Gunter%27s_chain" title="Gunter's chain">Gunter's chain</a> of 66 feet (20 m) which is subdivided into 4 rods, each of 16.5 ft or 100 links of 0.66 feet. A link is abbreviated "lk", and links "lks", in old deeds and land surveys done for the government. </p> <div class="mw-heading mw-heading2"><h2 id="Science">Science</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=10" title="Edit section: Science"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Astronomy">Astronomy</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=11" title="Edit section: Astronomy"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Astronomical_system_of_units" title="Astronomical system of units">Astronomical system of units</a></div> <p><a href="/wiki/Astronomy" title="Astronomy">Astronomical</a> measure uses: </p> <ul><li><a href="/wiki/Earth_radius" title="Earth radius">Earth radius</a> <var>R</var><sub>🜨</sub> ≈ 6,371 km<sup id="cite_ref-Moritz2000_9-0" class="reference"><a href="#cite_note-Moritz2000-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Lunar_distance_(astronomy)" class="mw-redirect" title="Lunar distance (astronomy)">Lunar distance</a> <i>LD</i> ≈ <span class="nowrap"><span data-sort-value="7008384402000000000♠"></span>384<span style="margin-left:.25em;">402</span> km</span>.<sup id="cite_ref-Apache_Point_10-0" class="reference"><a href="#cite_note-Apache_Point-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> Average distance between the center of Earth and the center of the Moon.</li> <li><a href="/wiki/Astronomical_unit" title="Astronomical unit">astronomical unit</a> au. Defined as <span class="nowrap"><span data-sort-value="7011149597870700000♠"></span>149<span style="margin-left:.25em;">597</span><span style="margin-left:.25em;">870</span><span style="margin-left:.25em;">700</span> m</span>.<sup id="cite_ref-Nature2012_11-0" class="reference"><a href="#cite_note-Nature2012-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> Approximately the distance between the Earth and Sun.</li> <li><a href="/wiki/Light-year" title="Light-year">light-year</a> ly ≈ <span class="nowrap"><span data-sort-value="7015946073047258080♠"></span>9<span style="margin-left:.25em;">460</span><span style="margin-left:.25em;">730</span><span style="margin-left:.25em;">472</span><span style="margin-left:.25em;">580</span>.8 km</span>. The distance that light travels in a <a href="/wiki/Vacuum" title="Vacuum">vacuum</a> in one <a href="/wiki/Julian_year_(astronomy)" title="Julian year (astronomy)">Julian year</a>.<sup id="cite_ref-IAUgen_12-0" class="reference"><a href="#cite_note-IAUgen-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Parsec" title="Parsec">parsec</a> pc ≈ <span class="nowrap"><span data-sort-value="7016308567758146719♠"></span>30<span style="margin-left:.25em;">856</span><span style="margin-left:.25em;">775</span><span style="margin-left:.25em;">814</span><span style="margin-left:.25em;">671</span>.9 km</span> or about <span class="nowrap"><span data-sort-value="7016308567400801506♠"></span>3.261<span style="margin-left:.25em;">56</span> ly</span></li> <li><a href="/wiki/Hubble%27s_law#Hubble_length" title="Hubble's law">Hubble length</a> 14.4 billion light-years or 4.55 gigaparsecs</li></ul> <div class="mw-heading mw-heading3"><h3 id="Physics">Physics</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=12" title="Edit section: Physics"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In atomic physics, sub-atomic physics, and cosmology, the preferred unit of length is often related to a chosen fundamental physical constant, or combination thereof. This is often a characteristic radius or wavelength of a particle. Some common <a href="/wiki/Natural_units" title="Natural units">natural units</a> of length are included in this table: </p> <table class="wikitable" style="margin-left: 20px;"> <tbody><tr> <th>Atomic property </th> <th>Symbol </th> <th>Length, in meters </th> <th>Reference </th></tr> <tr align="left"> <td>The classical electron radius </td> <td align="center"><i>r</i><sub><i>e</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6985281794028500000♠"></span>2.817<span style="margin-left:.25em;">940</span><span style="margin-left:.25em;">285</span>(31)<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−15</sup></span> </td> <td align="center"><sup id="cite_ref-Bohr_ruler_13-0" class="reference"><a href="#cite_note-Bohr_ruler-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td>The Compton wavelength of the electron </td> <td align="center"><i>λ</i><sub><i>C</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6988242631021500000♠"></span>2.426<span style="margin-left:.25em;">310</span><span style="margin-left:.25em;">215</span>(18)<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−12</sup></span> </td> <td align="center"><sup id="cite_ref-Bohr_ruler_13-1" class="reference"><a href="#cite_note-Bohr_ruler-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td>The reduced Compton wavelength of the electron </td> <td align="center"><s><i>λ</i></s><sub><i>C</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6987386159267640000♠"></span>3.861<span style="margin-left:.25em;">592</span><span style="margin-left:.25em;">6764</span>(18)<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−13</sup></span> </td> <td align="center"><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td>The Compton wavelength (or reduced Compton wavelength) of any fundamental particle </td> <td align="center"><s><i>λ</i></s><sub><i>x</i></sub> </td> <td> </td> <td> </td></tr> <tr> <td>The <a href="/wiki/Bohr_radius" title="Bohr radius">Bohr radius</a> of the hydrogen atom (<a href="/wiki/Atomic_unit" class="mw-redirect" title="Atomic unit">Atomic unit</a> of length) </td> <td align="center"><i>a</i><sub><i>0</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6989529177208299999♠"></span>5.291<span style="margin-left:.25em;">772</span><span style="margin-left:.25em;">083</span>(19)<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−11</sup></span> </td> <td align="center"><sup id="cite_ref-Bohr_ruler_13-2" class="reference"><a href="#cite_note-Bohr_ruler-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td>The reduced wavelength of hydrogen radiation </td> <td align="center">1 / <i>R</i><sub>∞</sub> </td> <td><span class="nowrap"><span data-sort-value="6992911267050550900♠"></span>9.112<span style="margin-left:.25em;">670</span><span style="margin-left:.25em;">505</span><span style="margin-left:.25em;">509</span>(83)<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−8</sup></span> </td> <td align="center"><sup id="cite_ref-Bohr_ruler_13-3" class="reference"><a href="#cite_note-Bohr_ruler-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td>The <a href="/wiki/Planck_length" class="mw-redirect" title="Planck length">Planck length</a> </td> <td align="center">𝓁<sub><i>P</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6965161619900000000♠"></span>1.616<span style="margin-left:.25em;">199</span>(97)<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−35</sup></span> </td> <td align="center"><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </td></tr> <tr> <td><a href="/wiki/Stoney_units" title="Stoney units">Stoney unit</a> of length </td> <td align="center"><i>l</i><sub><i>S</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6965138100000000000♠"></span>1.381<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−35</sup></span> </td> <td align="center"> </td></tr> <tr> <td>Quantum chromodynamics (<a href="/wiki/Quantum_chromodynamics" title="Quantum chromodynamics">QCD</a>) unit of length </td> <td align="center"><i>l</i><sub><i>QCD</i></sub> </td> <td><span class="nowrap"><span data-sort-value="6984210300000000000♠"></span>2.103<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−16</sup></span> </td> <td align="center"> </td></tr> <tr> <td>Natural units based on the electronvolt </td> <td align="center">1 eV<sup>−1</sup> </td> <td><span class="nowrap"><span data-sort-value="6993196999999999999♠"></span>1.97<span style="margin-left:0.25em;margin-right:0.15em;">×</span>10<sup>−7</sup></span> </td> <td align="center"> </td></tr></tbody></table> <div class="mw-heading mw-heading2"><h2 id="Archaic">Archaic</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=13" title="Edit section: Archaic"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/English_units#Length" title="English units">English units of length</a></div> <p><a href="/wiki/Archaism" title="Archaism">Archaic</a> units of distance include: </p> <ul><li><a href="/wiki/Cana_(unit)" title="Cana (unit)">cana</a></li> <li><a href="/wiki/Cubit" title="Cubit">cubit</a></li> <li><a href="/wiki/Rope_(unit)" title="Rope (unit)">rope</a></li> <li><a href="/wiki/League_(unit)" title="League (unit)">league</a></li> <li><a href="/wiki/Li_(unit)" title="Li (unit)">li</a> (China)</li> <li><a href="/wiki/Pace_(unit)" title="Pace (unit)">pace</a> (the "double pace" of about 5 feet used in <a href="/wiki/Ancient_Rome" title="Ancient Rome">Ancient Rome</a>)</li> <li><a href="/wiki/Verst" title="Verst">verst</a> (Russia)</li></ul> <div class="mw-heading mw-heading2"><h2 id="Informal">Informal</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=14" title="Edit section: Informal"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="/wiki/List_of_humorous_units_of_measurement" title="List of humorous units of measurement">List of humorous units of measurement</a> and <a href="/wiki/List_of_unusual_units_of_measurement" title="List of unusual units of measurement">List of unusual units of measurement</a></div> <p>In everyday conversation, and in informal literature, it is common to see lengths measured in units of objects of which everyone knows the approximate width. Common examples are: </p> <ul><li><a href="/wiki/Double-decker_bus" title="Double-decker bus">Double-decker bus</a> (9.5–11 meters in length)</li> <li><a href="/wiki/American_football" title="American football">American football</a> field (100 yards in length)</li> <li>Thickness of a human <a href="/wiki/Hair" title="Hair">hair</a> (around 80 micrometers)</li></ul> <div class="mw-heading mw-heading2"><h2 id="Other">Other</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=15" title="Edit section: Other"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Horse_racing" title="Horse racing">Horse racing</a> and other equestrian activities keep alive: </p> <ul><li><a href="/wiki/Furlong" title="Furlong">furlong</a> = <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1154941027"><span class="frac"><span class="num">1</span>⁄<span class="den">8</span></span> mile (201.168 m)</li> <li><a href="/wiki/Horse_length" title="Horse length">horse length</a> ≈ 8 feet (2.4 m)</li></ul> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=16" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/List_of_conversion_factors#Length" title="List of conversion factors">List of conversion factors § Length</a></li> <li><a href="/wiki/List_of_examples_of_lengths" class="mw-redirect" title="List of examples of lengths">List of examples of lengths</a></li> <li><a href="/wiki/List_of_unusual_units_of_measurement#Length" title="List of unusual units of measurement">List of unusual units of measurement § Length</a></li> <li><a href="/wiki/Medieval_weights_and_measures" title="Medieval weights and measures">Medieval weights and measures</a></li> <li><a href="/wiki/Orders_of_magnitude_(length)" title="Orders of magnitude (length)">Orders of magnitude (length)</a></li> <li><a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">System of measurement</a></li> <li><a href="/wiki/Units_of_measurement" class="mw-redirect" title="Units of measurement">Units of measurement</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=17" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFCardarelli2003" class="citation book cs1">Cardarelli, François (2003). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/encyclopaediaofs0000card"><i>Encyclopaedia of Scientific Units, Weights, and Measures: Their SI Equivalences and Origins</i></a></span>. Springer. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781852336820" title="Special:BookSources/9781852336820"><bdi>9781852336820</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Encyclopaedia+of+Scientific+Units%2C+Weights%2C+and+Measures%3A+Their+SI+Equivalences+and+Origins&rft.pub=Springer&rft.date=2003&rft.isbn=9781852336820&rft.aulast=Cardarelli&rft.aufirst=Fran%C3%A7ois&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fencyclopaediaofs0000card&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Hinkelman-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-Hinkelman_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Hinkelman_2-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHinkelmanSibylla_Putzi2005" class="citation book cs1">Hinkelman, Edward G.; Sibylla Putzi (2005). <i>Dictionary Of International Trade: Handbook Of The Global Trade Community</i>. World Trade Press. p. 245. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781885073723" title="Special:BookSources/9781885073723"><bdi>9781885073723</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Dictionary+Of+International+Trade%3A+Handbook+Of+The+Global+Trade+Community&rft.pages=245&rft.pub=World+Trade+Press&rft.date=2005&rft.isbn=9781885073723&rft.aulast=Hinkelman&rft.aufirst=Edward+G.&rft.au=Sibylla+Putzi&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJudson1960" class="citation book cs1">Judson, Lewis Van Hagen (1960). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Mialg1senzMC&q=Units+of+Weight+and+Measure+%28United+States+Customary+and+Metric%29"><i>Units of Weight and Measure (United States Customary and Metric): Definitions and Tables of Equivalents, Issue,233</i></a>. U.S. Department of Commerce, National Bureau of Standards. pp. 3–4<span class="reference-accessdate">. Retrieved <span class="nowrap">16 October</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Units+of+Weight+and+Measure+%28United+States+Customary+and+Metric%29%3A+Definitions+and+Tables+of+Equivalents%2C+Issue%2C233&rft.pages=3-4&rft.pub=U.S.+Department+of+Commerce%2C+National+Bureau+of+Standards&rft.date=1960&rft.aulast=Judson&rft.aufirst=Lewis+Van+Hagen&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DMialg1senzMC%26q%3DUnits%2Bof%2BWeight%2Band%2BMeasure%2B%2528United%2BStates%2BCustomary%2Band%2BMetric%2529&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Res1-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-Res1_4-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.bipm.org/en/CGPM/db/17/1/">"17th General Conference on Weights and Measures (1983), Resolution 1"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2012-09-19</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=17th+General+Conference+on+Weights+and+Measures+%281983%29%2C+Resolution+1.&rft_id=http%3A%2F%2Fwww.bipm.org%2Fen%2FCGPM%2Fdb%2F17%2F1%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Fenna2002-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-Fenna2002_5-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDonald_Fenna2002" class="citation book cs1">Donald Fenna (2002). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/dictionaryofweig0000fenn"><i>A dictionary of weights, measures, and units</i></a></span>. Oxford University Press. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/dictionaryofweig0000fenn/page/130">130</a>–131. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0198605225" title="Special:BookSources/978-0198605225"><bdi>978-0198605225</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">8 January</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+dictionary+of+weights%2C+measures%2C+and+units&rft.pages=130-131&rft.pub=Oxford+University+Press&rft.date=2002&rft.isbn=978-0198605225&rft.au=Donald+Fenna&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fdictionaryofweig0000fenn&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><a href="#CITEREFCardarelli2003">Cardarelli 2003</a>, pp. 29–30</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWilks,_Kevin_Joseph.1992" class="citation book cs1">Wilks, Kevin Joseph. (1992). <a rel="nofollow" class="external text" href="https://www.worldcat.org/oclc/27702954"><i>Metrication in Australia : a review of the effectiveness of policies and procedures in Australia's conversion to the metric system</i></a>. Australia. Department of Industry, Technology, and Commerce. Canberra: Australian Govt. Pub. Service. p. 94. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-644-24860-2" title="Special:BookSources/0-644-24860-2"><bdi>0-644-24860-2</bdi></a>. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/27702954">27702954</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Metrication+in+Australia+%3A+a+review+of+the+effectiveness+of+policies+and+procedures+in+Australia%27s+conversion+to+the+metric+system&rft.place=Canberra&rft.pages=94&rft.pub=Australian+Govt.+Pub.+Service&rft.date=1992&rft_id=info%3Aoclcnum%2F27702954&rft.isbn=0-644-24860-2&rft.au=Wilks%2C+Kevin+Joseph.&rft_id=https%3A%2F%2Fwww.worldcat.org%2Foclc%2F27702954&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://themetricmaven.com/wp-content/uploads/2012/03/Metrication-in-Australia-built-2013-06-24.pdf">"Metrication in Australia"</a> <span class="cs1-format">(PDF)</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Metrication+in+Australia&rft_id=http%3A%2F%2Fthemetricmaven.com%2Fwp-content%2Fuploads%2F2012%2F03%2FMetrication-in-Australia-built-2013-06-24.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Moritz2000-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-Moritz2000_9-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMoritz2000" class="citation journal cs1">Moritz, H. (March 2000). "Geodetic Reference System 1980". <i>Journal of Geodesy</i>. <b>74</b> (1): 128–133. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2000JGeod..74..128.">2000JGeod..74..128.</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs001900050278">10.1007/s001900050278</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:195290884">195290884</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Geodesy&rft.atitle=Geodetic+Reference+System+1980&rft.volume=74&rft.issue=1&rft.pages=128-133&rft.date=2000-03&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A195290884%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2Fs001900050278&rft_id=info%3Abibcode%2F2000JGeod..74..128.&rft.aulast=Moritz&rft.aufirst=H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Apache_Point-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-Apache_Point_10-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBattatMurphyAdelberger2009" class="citation journal cs1">Battat, J. B. R.; Murphy, T. W.; Adelberger, E. G. (January 2009). <a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F596748">"The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO): Two Years of Millimeter-Precision Measurements of the Earth-Moon Range"</a>. <i>Astronomical Society of the Pacific</i>. <b>121</b> (875): 29–40. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2009PASP..121...29B">2009PASP..121...29B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F596748">10.1086/596748</a></span>. <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/10.1086/596748">10.1086/596748</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Astronomical+Society+of+the+Pacific&rft.atitle=The+Apache+Point+Observatory+Lunar+Laser-ranging+Operation+%28APOLLO%29%3A+Two+Years+of+Millimeter-Precision+Measurements+of+the+Earth-Moon+Range&rft.volume=121&rft.issue=875&rft.pages=29-40&rft.date=2009-01&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F10.1086%2F596748%23id-name%3DJSTOR&rft_id=info%3Adoi%2F10.1086%2F596748&rft_id=info%3Abibcode%2F2009PASP..121...29B&rft.aulast=Battat&rft.aufirst=J.+B.+R.&rft.au=Murphy%2C+T.+W.&rft.au=Adelberger%2C+E.+G.&rft_id=https%3A%2F%2Fdoi.org%2F10.1086%252F596748&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Nature2012-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-Nature2012_11-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGeoff_Brumfiel2012" class="citation web cs1">Geoff Brumfiel (14 Sep 2012). <a rel="nofollow" class="external text" href="http://www.nature.com/news/the-astronomical-unit-gets-fixed-1.11416">"The astronomical unit gets fixed: Earth–Sun distance changes from slippery equation to single number"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">14 Sep</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+astronomical+unit+gets+fixed%3A+Earth%E2%80%93Sun+distance+changes+from+slippery+equation+to+single+number.&rft.date=2012-09-14&rft.au=Geoff+Brumfiel&rft_id=http%3A%2F%2Fwww.nature.com%2Fnews%2Fthe-astronomical-unit-gets-fixed-1.11416&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-IAUgen-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-IAUgen_12-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://www.iau.org/public_press/themes/measuring/"><i>The IAU and astronomical units</i></a>, International Astronomical Union<span class="reference-accessdate">, retrieved <span class="nowrap">2008-07-05</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+IAU+and+astronomical+units&rft.pub=International+Astronomical+Union&rft_id=http%3A%2F%2Fwww.iau.org%2Fpublic_press%2Fthemes%2Fmeasuring%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-Bohr_ruler-13"><span class="mw-cite-backlink">^ <a href="#cite_ref-Bohr_ruler_13-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Bohr_ruler_13-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Bohr_ruler_13-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Bohr_ruler_13-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFQuinnLeschiuttaTavella2000" class="citation book cs1">Quinn, T.J.; Leschiutta, S.; Tavella, P. (August 2000). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WE22Fez60EcC&q=bohr+ruler&pg=PA142"><i>Recent advances in metrology and fundamental constants</i></a>. Amsterdam; Washington, DC: IOS Press, 2001. Proceedings of the International School of Physics "Enrico Fermi". pp. 142–143. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781586031671" title="Special:BookSources/9781586031671"><bdi>9781586031671</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Recent+advances+in+metrology+and+fundamental+constants&rft.place=Amsterdam%3B+Washington%2C+DC&rft.pages=142-143&rft.pub=IOS+Press%2C+2001.+Proceedings+of+the+International+School+of+Physics+%22Enrico+Fermi%22&rft.date=2000-08&rft.isbn=9781586031671&rft.aulast=Quinn&rft.aufirst=T.J.&rft.au=Leschiutta%2C+S.&rft.au=Tavella%2C+P.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DWE22Fez60EcC%26q%3Dbohr%2Bruler%26pg%3DPA142&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://physics.nist.gov/cgi-bin/cuu/Value?ecomwlbar">"Compton wavelength over 2 pi"</a>. <i>The NIST Reference on Constants, Units, and Uncertainty</i>. NIST<span class="reference-accessdate">. Retrieved <span class="nowrap">15 October</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+NIST+Reference+on+Constants%2C+Units%2C+and+Uncertainty&rft.atitle=Compton+wavelength+over+2+pi&rft_id=http%3A%2F%2Fphysics.nist.gov%2Fcgi-bin%2Fcuu%2FValue%3Fecomwlbar&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://physics.nist.gov/cgi-bin/cuu/Value?plkl">"Planck length"</a>. <i>The NIST Reference on Constants, Units, and Uncertainty</i>. <a href="/wiki/NIST" class="mw-redirect" title="NIST">NIST</a><span class="reference-accessdate">. Retrieved <span class="nowrap">15 October</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+NIST+Reference+on+Constants%2C+Units%2C+and+Uncertainty&rft.atitle=Planck+length&rft_id=http%3A%2F%2Fphysics.nist.gov%2Fcgi-bin%2Fcuu%2FValue%3Fplkl&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Unit_of_length&action=edit&section=18" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWhitelaw2007" class="citation book cs1">Whitelaw, Ian (2007). <i>A Measure of All Things: The Story of Man and Measurement</i>. Macmillan. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780312370268" title="Special:BookSources/9780312370268"><bdi>9780312370268</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Measure+of+All+Things%3A+The+Story+of+Man+and+Measurement&rft.pub=Macmillan&rft.date=2007&rft.isbn=9780312370268&rft.aulast=Whitelaw&rft.aufirst=Ian&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUnit+of+length" class="Z3988"></span></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline 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title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Systems_of_measurement" title="Template talk:Systems of measurement"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Systems_of_measurement" title="Special:EditPage/Template:Systems of measurement"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Systems_of_measurement" style="font-size:114%;margin:0 4em"><a href="/wiki/System_of_measurement" class="mw-redirect" title="System of measurement">Systems of measurement</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Current</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em">General</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units (SI)</a></li> <li><a href="/wiki/Imperial_units" title="Imperial units">UK imperial system</a></li> <li><a href="/wiki/United_States_customary_units" title="United States customary units">US customary units (USCS/USC)</a></li> <li><a href="/wiki/Chinese_units_of_measurement" title="Chinese units of measurement">Chinese</a> <ul><li><a href="/wiki/Hong_Kong_units_of_measurement" title="Hong Kong units of measurement">Hong Kong</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Specific</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apothecaries%27_system" title="Apothecaries' system">Apothecaries'</a></li> <li><a href="/wiki/Avoirdupois_system" class="mw-redirect" title="Avoirdupois system">Avoirdupois</a></li> <li><a href="/wiki/Troy_weight" title="Troy weight">Troy</a></li> <li><a href="/wiki/Astronomical_system_of_units" title="Astronomical system of units">Astronomical</a></li> <li><a href="/wiki/Conventional_electrical_unit" title="Conventional electrical unit">Electrical</a></li> <li><a href="/wiki/English_Engineering_Units" title="English Engineering Units">English Engineering Units</a> (US)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Natural_units" title="Natural units">Natural</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Atomic_units" title="Atomic units">Atomic</a></li> <li><a href="/wiki/Geometrized_unit_system" title="Geometrized unit system">Geometrised</a></li> <li><a href="/wiki/Heaviside%E2%80%93Lorentz_units" title="Heaviside–Lorentz units">Heaviside–Lorentz</a></li> <li><a href="/wiki/Planck_units" title="Planck units">Planck</a></li> <li><a href="/wiki/Natural_units#Quantum_chromodynamics_units" title="Natural units">Quantum chromodynamical</a></li> <li><a href="/wiki/Stoney_units" title="Stoney units">Stoney</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Background</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em">Metric</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Metric_system" title="Metric system">Overview</a></li> <li><a href="/wiki/Outline_of_the_metric_system" title="Outline of the metric system">Outline</a></li> <li><a href="/wiki/History_of_the_metric_system" title="History of the metric system">History</a></li> <li><a href="/wiki/Metrication" title="Metrication">Metrication</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">UK/US</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Imperial_and_US_customary_measurement_systems" title="Imperial and US customary measurement systems">Overview</a></li> <li><a href="/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems" title="Comparison of the imperial and US customary measurement systems">Comparison</a></li> <li><a href="/wiki/Foot%E2%80%93pound%E2%80%93second_system" class="mw-redirect" title="Foot–pound–second system">Foot–pound–second</a> (FPS)</li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Historic</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em">Metric</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/MKS_system_of_units" class="mw-redirect" title="MKS system of units">metre–kilogram–second</a> (MKS)</li> <li><a href="/wiki/Metre%E2%80%93tonne%E2%80%93second_system_of_units" title="Metre–tonne–second system of units">metre–tonne–second</a> (MTS)</li> <li><a href="/wiki/Centimetre%E2%80%93gram%E2%80%93second_system_of_units" title="Centimetre–gram–second system of units">centimetre–gram–second</a> (CGS)</li> <li><a href="/wiki/Gravitational_metric_system" title="Gravitational metric system">gravitational</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Europe</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Old_Cornish_units_of_measurement" title="Old Cornish units of measurement">Cornish</a></li> <li><a href="/wiki/Cypriot_units_of_measurement" title="Cypriot units of measurement">Cypriot</a></li> <li><a href="/wiki/Czech_units_of_measurement" title="Czech units of measurement">Czech</a></li> <li><a href="/wiki/Danish_units_of_measurement" title="Danish units of measurement">Danish</a></li> <li><a href="/wiki/Dutch_units_of_measurement" title="Dutch units of measurement">Dutch</a></li> <li><a href="/wiki/English_units" title="English units">English</a> <ul><li><a href="/wiki/Winchester_measure" title="Winchester measure">Winchester</a></li> <li><a href="/wiki/Exchequer_Standards" title="Exchequer Standards">Exchequer</a></li></ul></li> <li><a href="/wiki/Estonian_units_of_measurement" title="Estonian units of measurement">Estonian</a></li> <li><a href="/wiki/Obsolete_Finnish_units_of_measurement" title="Obsolete Finnish units of measurement">Finnish</a></li> <li><a href="/wiki/French_units_of_measurement" title="French units of measurement">French</a> <ul><li><a href="/wiki/Traditional_French_units_of_measurement" title="Traditional French units of measurement">Traditional</a></li> <li><a href="/wiki/Mesures_usuelles" title="Mesures usuelles">Mesures usuelles</a></li></ul></li> <li><a href="/wiki/Obsolete_German_units_of_measurement" class="mw-redirect" title="Obsolete German units of measurement">German</a></li> <li><a href="/wiki/Greek_units_of_measurement" title="Greek units of measurement">Greek</a> <ul><li><a href="/wiki/Byzantine_units_of_measurement" title="Byzantine units of measurement">Byzantine</a></li></ul></li> <li><a href="/wiki/Hungarian_units_of_measurement" title="Hungarian units of measurement">Hungarian</a></li> <li><a href="/wiki/Icelandic_units_of_measurement" title="Icelandic units of measurement">Icelandic</a></li> <li><a href="/wiki/Old_Irish_units_of_measurement" class="mw-redirect" title="Old Irish units of measurement">Irish</a></li> <li><a href="/wiki/Italian_units_of_measurement" title="Italian units of measurement">Italian</a></li> <li><a href="/wiki/Latvian_units_of_measurement" title="Latvian units of measurement">Latvian</a></li> <li><a href="/wiki/Luxembourgian_units_of_measurement" class="mw-redirect" title="Luxembourgian units of measurement">Luxembourgian</a></li> <li><a href="/wiki/Maltese_units_of_measurement" title="Maltese units of measurement">Maltese</a></li> <li><a href="/wiki/Norwegian_units_of_measurement" title="Norwegian units of measurement">Norwegian</a></li> <li><a href="/wiki/Ottoman_units_of_measurement" title="Ottoman units of measurement">Ottoman</a></li> <li><a href="/wiki/Polish_units_of_measurement" title="Polish units of measurement">Polish</a></li> <li><a href="/wiki/Portuguese_units_of_measurement" title="Portuguese units of measurement">Portuguese</a></li> <li><a href="/wiki/Romanian_units_of_measurement" title="Romanian units of measurement">Romanian</a></li> <li><a href="/wiki/Obsolete_Russian_units_of_measurement" class="mw-redirect" title="Obsolete Russian units of measurement">Russian</a></li> <li><a href="/wiki/Scottish_units" title="Scottish units">Scottish</a></li> <li><a href="/wiki/Obsolete_Serbian_units_of_measurement" title="Obsolete Serbian units of measurement">Serbian</a></li> <li><a href="/wiki/Slovak_units_of_measurement" title="Slovak units of measurement">Slovak</a></li> <li><a href="/wiki/Spanish_units_of_measurement" title="Spanish units of measurement">Spanish</a></li> <li><a href="/wiki/Swedish_units_of_measurement" title="Swedish units of measurement">Swedish</a></li> <li><a href="/wiki/Swiss_units_of_measurement" title="Swiss units of measurement">Swiss</a></li> <li><a href="/wiki/Welsh_units" title="Welsh units">Welsh</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Asia</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Afghan_units_of_measurement" title="Afghan units of measurement">Afghan</a></li> <li><a href="/wiki/Cambodian_units_of_measurement" title="Cambodian units of measurement">Cambodian</a></li> <li><a href="/wiki/Indian_units_of_measurement" title="Indian units of measurement">Indian</a></li> <li><a href="/wiki/Indonesian_units_of_measurement" title="Indonesian units of measurement">Indonesian</a></li> <li><a href="/wiki/Japanese_units_of_measurement" title="Japanese units of measurement">Japanese</a></li> <li><a href="/wiki/Korean_units_of_measurement" title="Korean units of measurement">Korean</a></li> <li><a href="/wiki/Mongolian_units" title="Mongolian units">Mongolian</a></li> <li><a href="/wiki/Myanmar_units_of_measurement" title="Myanmar units of measurement">Myanmar</a></li> <li><a href="/wiki/Nepalese_customary_units_of_measurement" title="Nepalese customary units of measurement">Nepalese</a></li> <li><a href="/wiki/Omani_units_of_measurement" title="Omani units of measurement">Omani</a></li> <li><a href="/wiki/History_of_measurement_systems_in_Pakistan" title="History of measurement systems in Pakistan">Pakistani</a></li> <li><a href="/wiki/Philippine_units_of_measurement" title="Philippine units of measurement">Philippine</a></li> <li><a href="/wiki/Abucco" title="Abucco">Pegu</a></li> <li><a href="/wiki/Singaporean_units_of_measurement" title="Singaporean units of measurement">Singaporean</a></li> <li><a href="/wiki/Sri_Lankan_units_of_measurement" title="Sri Lankan units of measurement">Sri Lankan</a></li> <li><a href="/wiki/Syrian_units_of_measurement" title="Syrian units of measurement">Syrian</a></li> <li><a href="/wiki/Taiwanese_units_of_measurement" title="Taiwanese units of measurement">Taiwanese</a></li> <li><a href="/wiki/Obsolete_Tatar_units_of_measurement" class="mw-redirect" title="Obsolete Tatar units of measurement">Tatar</a></li> <li><a href="/wiki/Thai_units_of_measurement" title="Thai units of measurement">Thai</a></li> <li><a href="/wiki/Vietnamese_units_of_measurement" title="Vietnamese units of measurement">Vietnamese</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Africa</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Algerian_units_of_measurement" title="Algerian units of measurement">Algerian</a></li> <li><a href="/wiki/Ethiopian_units_of_measurement" title="Ethiopian units of measurement">Ethiopian</a></li> <li><a href="/wiki/Egyptian_units_of_measurement" title="Egyptian units of measurement">Egyptian</a></li> <li><a href="/wiki/Eritrean_units_of_measurement" title="Eritrean units of measurement">Eritrean</a></li> <li><a href="/wiki/Guinean_units_of_measurement" title="Guinean units of measurement">Guinean</a></li> <li><a href="/wiki/Libyan_units_of_measurement" title="Libyan units of measurement">Libyan</a></li> <li><a href="/wiki/Malagasy_units_of_measurement" title="Malagasy units of measurement">Malagasy</a></li> <li><a href="/wiki/Mauritian_units_of_measurement" title="Mauritian units of measurement">Mauritian</a></li> <li><a href="/wiki/Moroccan_units_of_measurement" title="Moroccan units of measurement">Moroccan</a></li> <li><a href="/wiki/Seychellois_units_of_measurement" title="Seychellois units of measurement">Seychellois</a></li> <li><a href="/wiki/Somali_units_of_measurement" title="Somali units of measurement">Somali</a></li> <li><a href="/wiki/South_African_units_of_measurement" title="South African units of measurement">South African</a></li> <li><a href="/wiki/Tunisian_units_of_measurement" title="Tunisian units of measurement">Tunisian</a></li> <li><a href="/wiki/Tanzanian_units_of_measurement" title="Tanzanian units of measurement">Tanzanian</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">North America</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Costa_Rican_units_of_measurement" title="Costa Rican units of measurement">Costa Rican</a></li> <li><a href="/wiki/Cuban_units_of_measurement" title="Cuban units of measurement">Cuban</a></li> <li><a href="/wiki/Haitian_units_of_measurement" title="Haitian units of measurement">Haitian</a></li> <li><a href="/wiki/Honduran_units_of_measurement" title="Honduran units of measurement">Honduran</a></li> <li><a href="/wiki/Mexican_units_of_measurement" title="Mexican units of measurement">Mexican</a></li> <li><a href="/wiki/Nicaraguan_units_of_measurement" title="Nicaraguan units of measurement">Nicaraguan</a></li> <li><a href="/wiki/Puerto_Rican_units_of_measurement" title="Puerto Rican units of measurement">Puerto Rican</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">South America</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Argentine_units_of_measurement" title="Argentine units of measurement">Argentine</a></li> <li><a href="/wiki/Bolivian_units_of_measurement" title="Bolivian units of measurement">Bolivian</a></li> <li><a href="/wiki/Brazilian_units_of_measurement" title="Brazilian units of measurement">Brazilian</a></li> <li><a href="/wiki/Chilean_units_of_measurement" title="Chilean units of measurement">Chilean</a></li> <li><a href="/wiki/Colombian_units_of_measurement" title="Colombian units of measurement">Colombian</a></li> <li><a href="/wiki/Paraguayan_units_of_measurement" title="Paraguayan units of measurement">Paraguayan</a></li> <li><a href="/wiki/Peruvian_units_of_measurement" title="Peruvian units of measurement">Peruvian</a></li> <li><a href="/wiki/Uruguayan_units_of_measurement" title="Uruguayan units of measurement">Uruguayan</a></li> <li><a href="/wiki/Venezuelan_units_of_measurement" title="Venezuelan units of measurement">Venezuelan</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Ancient</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ancient_Arabic_units_of_measurement" title="Ancient Arabic units of measurement">Arabic</a></li> <li><a href="/wiki/Biblical_and_Talmudic_units_of_measurement" title="Biblical and Talmudic units of measurement">Biblical and Talmudic</a></li> <li><a href="/wiki/Ancient_Egyptian_units_of_measurement" title="Ancient Egyptian units of measurement">Egyptian</a></li> <li><a href="/wiki/Ancient_Greek_units_of_measurement" title="Ancient Greek units of measurement">Greek</a></li> <li><a href="/wiki/Hindu_units_of_time" title="Hindu units of time">Hindu</a></li> <li><a href="/wiki/History_of_measurement_systems_in_India" title="History of measurement systems in India">Indian</a></li> <li><a href="/wiki/Ancient_Mesopotamian_units_of_measurement" title="Ancient Mesopotamian units of measurement">Mesopotamian</a></li> <li><a href="/wiki/Persian_units_of_measurement" title="Persian units of measurement">Persian</a></li> <li><a href="/wiki/Ancient_Roman_units_of_measurement" title="Ancient Roman units of measurement">Roman</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">List articles</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_humorous_units_of_measurement" title="List of humorous units of measurement">Humorous</a></li> <li><a href="/wiki/List_of_obsolete_units_of_measurement" title="List of obsolete units of measurement">Obsolete</a></li> <li><a href="/wiki/List_of_unusual_units_of_measurement" title="List of unusual units of measurement">Unusual</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Absolute_scale" title="Absolute scale">Absolute scale</a></li> <li><a href="/wiki/N-body_units" title="N-body units">N-body</a></li> <li><a href="/wiki/Modulor" title="Modulor">Modulor</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Units_of_length_used_in_Astronomy" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Units_of_length_used_in_Astronomy" title="Template:Units of length used in Astronomy"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Units_of_length_used_in_Astronomy" title="Template talk:Units of length used in Astronomy"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Units_of_length_used_in_Astronomy" title="Special:EditPage/Template:Units of length used in Astronomy"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Units_of_length_used_in_Astronomy" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Units of length</a> used in <a href="/wiki/Astronomy" title="Astronomy">Astronomy</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><a href="/wiki/Astronomical_system_of_units" title="Astronomical system of units">Astronomical system of units</a></li></ul> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Earth_radius_(unit)" class="mw-redirect" title="Earth radius (unit)">Earth radius</a> (<var>R</var><sub>🜨</sub> or <i>R<sub>E</sub></i>)</li> <li><a href="/wiki/Light-second" title="Light-second">Light-second</a> (ls)</li> <li><a href="/wiki/Solar_radius" title="Solar radius">Solar radius</a> (<var>R</var><sub>☉</sub>)</li> <li><a href="/wiki/Gigametre" class="mw-redirect" title="Gigametre">gigametre</a> (Gm)</li> <li><a href="/wiki/Astronomical_unit" title="Astronomical unit">Astronomical unit</a> (au)</li> <li><a href="/wiki/Terametre" class="mw-redirect" title="Terametre">terametre</a> (Tm)</li> <li><a href="/wiki/Light-year" title="Light-year">light-year</a> (ly)</li> <li><a href="/wiki/Parsec" title="Parsec">parsec</a> (pc)</li> <li><a href="/wiki/Kiloparsec" class="mw-redirect" title="Kiloparsec">kiloparsec</a> (kpc)</li> <li><a href="/wiki/Megaparsec" class="mw-redirect" title="Megaparsec">megaparsec</a> (Mpc)</li> <li><a href="/wiki/Gigaparsec" class="mw-redirect" title="Gigaparsec">gigaparsec</a> (Gpc)</li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <dl><dt>See also</dt> <dd><a href="/wiki/Cosmic_distance_ladder" title="Cosmic distance ladder">Cosmic distance ladder</a></dd> <dd><a href="/wiki/Orders_of_magnitude_(length)" title="Orders of magnitude (length)">Orders of magnitude (length)</a></dd> <dd><a href="/wiki/Conversion_of_units" title="Conversion of units">Conversion of units</a></dd></dl> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"><style data-mw-deduplicate="TemplateStyles:r1038841319">.mw-parser-output .tooltip-dotted{border-bottom:1px dotted;cursor:help}</style></div><div role="navigation" class="navbox authority-control" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q1978718#identifiers" title="Edit 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