1 metre

To help compare different orders of magnitude this page lists lengths between one metre and ten metres. Light travels 1 metre in 1/299,792,458 of a second.

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1 metre is:

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Metre

The metre, or meter (American spelling), (from the Greek noun μέτρον, "measure") is the base unit of length in the International System of Units (SI). The SI unit symbol is m. The metre is defined as the distance travelled by light in a specific fraction (1/299 792 458) of a second.

The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole. In 1889, it was redefined in terms of a prototype metre bar (the actual bar used was subsequently changed twice). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted.

The imperial inch is defined as 0.0254 metres (2.54 centimetres or 25.4 millimetres). One metre is about 3 ³⁄₈ inches longer than a yard, i.e. about 39 ³⁄₈ inches.

Spelling

Metre is the standard spelling of the metric unit for length in all English-speaking nations except the USA, which uses meter.

Measuring devices (such as ammeter, speedometer) are spelled "-meter" in all countries. The word "meter", signifying any such device, has the same derivation as the word "metre", denoting the unit of length.