Klick
Military slang for a kilometer, used across human space and aboard most warships as the working unit for range.
A kilometer, in the mouth of a soldier or a ship's crew, is a klick. The slang is in use across human space, aboard most military vessels and some civilian ones, where it is the working unit for the distance to whatever the sensors are holding. It stays useful well past a million of them, at which point the astronomical unit takes over. The word goes back to the Vietnam War, where Australian troops counted a klick by the click a rifle made on reloading, one for every thousand meters walked in a straight line, and the United States military picked it up from there.
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