In military terms, a "klick" (spelled with a k) means a distance of one kilometer, or .62 miles. So, if a soldier radios, "We're 200 klicks south of your position" that means they are 200 kilometers away, or about 124 miles away.
The definition of "klick" can be found in several on-line glossaries (see links below):
www.capmarine.com
www.pbs.org
In "military-speak," the term "click" (spelled with a "c" instead of a "k") is used when sighting-in a weapon, such as a rifle. On most weapons, one "click" equals one minute of arc, or -- in other words, one inch of distance at one hundred yards.
So, moving the site adjustments of the rifle "one click" will change the point of impact one inch for a target 100 yards away, two inches for a target 200 yards away, and so forth.
Visit MilitaryTerms.net which contains one of the most comprehensive lists of military terms and definitions available online.