n (chiefly|US|elsewhere metre) The base unit of length in the International System of Units (SI), conceived of as 1/10000000 of the distance from the North Pole to the Equator, and now defined as the distance light will travel in a vacuum in 1/299792458 second.
n (chiefly|US|elsewhere metre) (music) an increment of music; the overall rhythm; particularly, the number of beats in a measure.