n. (US meter) a metric unit and the base SI unit of linear measure, equal to about 39.4 inches, and reckoned as the length of the path travelled by light in a vacuum during 1/299,792,458 of a second. metre-kilogram-second denoting a system of measure using the metre, kilogram, and second as the basic units of length, mass, and time. °Abbr.: mks. metreage n.
[ F mètre f. Gk metron measure ]