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Siq'i 1:
{{yachapakuq}}{{trad|art=metre|ci=en}}{{Unit of length|name=metro (icha mitru)|m=1|accuracy=4}}'''Mitru''' icha '''metro''' nisqaqa ([[grigu simi]]manta: ''μέτρον [métron] = tupuy'', chaymanta [[español simi]]pi: ''metro'') [[karu kay tupu]]m [[SI tupuy]]pi. Sut'inchaku: [[achkiy]]pa ch'usaqpi purisqan karu kay 1/299 792 458 [[sikundu]]pi (3,34 [[nanusikundu]]-
<!--The '''metre''' [[American English|or]] '''meter'''(symbol: '''m''') is the [[SI base unit|fundamental unit]] of [[length]] in the [[International System of Units]] (SI). The metre was originally defined by a prototype object meant to represent {{frac|10 000 000}} the distance between the [[Geographical pole|pole]]s and the [[Equator]]. Today, it is defined as {{frac|299 792 458}} of a [[Speed of light|light-second]].
Siq'i 64:
Note that this definition had the effect of fixing the speed of light in a vacuum at precisely 299<FONT SIZE="-2"> </FONT>792<FONT SIZE="-2"> </FONT>458 metres per second. Although the metre is now ''defined'' in terms of time-of-flight, actual laboratory realisations of the metre are still ''delineated'' by counting the required number of wavelengths of light along the distance. An intended byproduct of the 17<sup>th</sup> CGPM’s definition was that it enabled scientists to measure the wavelength of their lasers with one-fifth the uncertainty. To further facilitate reproducibility from lab to lab, the 17<sup>th</sup> CGPM also made the iodine-stabilised helium-neon laser "a recommended radiation" for realising the metre. Today's best determination of the wavelength of the relevant transition in <sup>127</sup>I<sub>2</sub> used for this purpose is λ = 632<FONT SIZE="-2"> </FONT>991<FONT SIZE="-2"> </FONT>212.58 fm with an estimated relative standard uncertainty ''(U)'' of 2.1 × 10<sup>-11</sup>. This uncertainty is currently the limiting factor in laboratory realisations of the metre as it is several orders of magnitude poorer than that of the second (''U'' = 5 × 10<sup>-16</sup>)<ref>[http://tf.nist.gov/timefreq/cesium/fountain.htm NIST-F1 Cesium Fountain Atomic Clock].</ref> Consequently, a practical realisation of the metre is usually delineated (not defined) today in labs as 1<FONT SIZE="-2"> </FONT>579<FONT SIZE="-2"> </FONT>800.762<FONT SIZE="-2"> </FONT>042(33) wavelengths of helium-neon laser light in a vacuum.-->
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