A metre (US spelling, meter) is the basic unit of length in the SI measurement system. The symbol for the metre is m. The first meaning (in the French Revolution) was one tenmillionth of the distance between the Earth's equator and the North Pole along the Paris meridian. The metre is now defined as the distance light travels in a vacuum in 1/299,792,458 of a second.
In the imperial system of measurement, one yard is 0.9144 metres (after international agreement in 1959), so a metre is very close to 39.37 inches: about 3.281 feet, or 1.0936 yards.
Units multiples
 0.000 000 000 000 000 000 000 001 Ym (yottametre) = 1 m
 0.000 000 000 000 000 000 001 Zm (zettametre) = 1 m
 0.000 000 000 000 000 001 Em (exametre) = 1 m
 0.000 000 000 000 001 Pm (petametre) = 1 m
 0.000 000 000 001 Tm (terametre) = 1 m
 0.000 000 001 Gm (gigametre) = 1 m
 0.000 001 Mm (megametre) = 1 m
 0.001 km (kilometre) = 1 m
 0.01 hm (hectometre) = 1 m
 0.1 dam(decametre) = 1 m
 1 m (metre)
 10 dm (decimetres) = 1 m
 100 cm (centimetres) = 1 m
 1000 mm (millimetres) = 1 m
 1 000 000 μm (micron or micrometres) = 1 m
 1 000 000 000 nm (nanometres) = 1 m
 1 000 000 000 000 pm (picometres) = 1 m
 1 000 000 000 000 000 fm (fermi or femtometres) = 1 m
 1 000 000 000 000 000 000 am (attometres) = 1 m
 1 000 000 000 000 000 000 000 zm (zeptometres) = 1 m
 1 000 000 000 000 000 000 000 000 ym (yoctometres) = 1 m
*Note: units in bold are the most commonly used.

Images for kids

Paris Panthéon

Triangulation near New York City, 1817.

Closeup of National Prototype Metre Bar No. 27, made in 1889 by the International Bureau of Weights and Measures (BIPM) and given to the United States, which served as the standard for defining all units of length in the US from 1893 to 1960