(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