How far is a click (american army slang for distance)?
Klick (sometimes spelled click, which may also mean one minute of arc when adjusting the sighting system on a weapon such as a rifle) is a common military term meaning kilometer when referring to distance or kilometers per hour (km/h) when referring to speed. Its use became popular among soldiers in Vietnam during the 1960s, although veterans of the war recall its usage as early as the 1950s. The term is of unknown origin. It is most likely an example of condensed pronunciation or contraction of the term kilometer, although other theories exist.
