The kilometer (from the Greek word for “thousand”) is a unit of length, equal to 1000 meters. It was first proposed in 1875 by the French scientist Georges Le Verneur, and was first used in 1880. The SI base unit of measurement is the meter, but since 2006, the kilometer has been recognized as an official unit of measure by the General Conference on Weights and Measures (CGPM), alongside the meter, kilogram and second. The kilometer is not officially defined, but it is based on the distance that light travels in a vacuum in 1/299.792 of a second.

The mile is a unit of length in the metric system, equal to 1.60931 kilometers. It is also the basic distance unit used throughout the United States of America and many countries of the world. The word “mile” comes from the Latin word for “a thousand paces,” although its actual origins are still debated by scholars. The Romans used it to measure distances from one water source or naval station to another. Over time, other units were also derived from the mile, including the yard, league, foot and inch. Today, various definitions of the mile exist, but it is most commonly defined as 3,280 feet or 1.609 kilometers.