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.

The yard is the traditional length unit of linear measure. It is traditionally equivalent to 0.9144 meters, though it has been varied between 9 and 12 feet in recent times. The yard was first conceptualized by fifth-century BC Egyptians and was standardized as 9 feet in 1795 by the French military engineer General Hoche. During the American Revolutionary War, the Continental Army was unimpressed with various proposals for a new foot measuring system and instead adopted the British yard as their standard. The use of the yard spread rapidly throughout the world after that due to its international compatibility. Today, most countries use either the metric system or a variant of it, and there are few remaining areas where yards are used; Africa mostly uses meters, India uses centimeters, parts of Asia use traditional units like li and fen.