This giraffe is nearly five metres tall. 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 ten-millionth of the distance between the Earth 's equator and the North Pole along the Paris meridian .[ 1] The metre is now defined as the distance light travels in a vacuum in 1/299,792,458 of a second .[ 1]
In the imperial system of measurement, one yard is 0.9144 metres (after international agreement in 1959), so a metre is very near to 39.37 inches : about 3.281 feet , or 1.0936 yards .
The bar (made of platinum and iridium ) that defined the length of a metre until 1960. 0.000 000 000 000 000 000 000 001 Ym (yotametre) = 1 m
0.000 000 000 000 000 000 001 Zm (zetametre) = 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 (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
Base units Units based on other units Other SI units See also