In the military, a "klick" is a term used to denote a distance of one kilometer or 1,000 meters. The term "klick" is believed to have originated from the sound of a military odometer, which made a "click" noise every time a soldier completed a mark of 1,000 meters by moving the gas regulator on their rifle with their thumb. Soldiers also use the term "click" when sighting-in a weapon, which refers to adjusting the weapons sights. In summary, a "klick" is a slang term for a kilometer and is used by the military to communicate distances.