The metre, or meter (US), is a measure of length. It is the basic unit of length in the metric system and in the International System of Units (SI), used around the world for general and scientific purposes. The symbol for metre is m. Historically, the metre was defined by the French Academy of Sciences as 1/10,000,000 of the distance from the equator to the north pole through Paris. Now, it is defined by the International Bureau of Weights and Measures as the distance travelled by light in absolute vacuum in 1/299,792,458 of a second. This is approximately the distance from floor to hip bone on the average barefoot man.