(From the Greek *metron* (*μετρον*), "a measure" via the French *mètre* and the Latin *metrum*) The basic unit of length in the International System of units, defined by the Conférence Générale des Poids et Mesures in 1983
to be the distance light travels in a vacuum during a time interval of 1/299,792,458 of a second, thus fixing the length of a meter in terms of time and the speed of light. One meter is equal to 39.3701 inches.

Symbol: m

Also spelled:

metre