What does a click mean in the military?

In the military, a click is slang for a kilometer, and it is more commonly spelled klick. The term is used by US and NATO forces as shorthand for measuring distance on the ground, especially when navigating, calling in artillery, or estimating how far a patrol must travel. For example, a soldier might say The objective is five klicks north, meaning five kilometers away, or We have hiked ten clicks today. The origin of the term is debated, but most historians trace it to the Vietnam War era where soldiers used maps with grid lines and the sound of the odometer or the rifle's adjustment clicking once per kilometer became associated with distance. Another theory is that it comes from the sound of a map's measuring tool clicking. A click can also refer to a small adjustment of a weapon's sights, such as one click equals one minute of angle, but when used as a distance, it is strictly one kilometer or about 0.62 miles. So if a military member says We are 2 clicks out, they mean they are 2 kilometers from the destination.