A kilometre (American spelling: kilometer, symbol km) is a unit of length in the metric system, equal to one thousand metres, the current SI base unit of length. It can be written in scientific notations as 1×10³ m (engineering notation) or (exponential notation) — both meaning . A corresponding unit of area is the square kilometre and a corresponding unit of volume is the cubic kilometre. Although, in English, metric units of measurement are usually pronounced with the stre… (More on Kilometer)