Klick (sometimes spelled click, but that 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. Its origin is sometimes linked with the Australian Army in Korea during the Korean War.
