A klick, alternately spelled "click," is 0.62 miles, according to the Public Broadcasting Service. The term "klick" is used as a shortened form of the word "kilometer." The word "klick," when used as a slang term to reference a kilometer, is considered to be a military term.
A klick is equal to 1,000 meters. The Internet Public Library notes that use of the word "klick" as military slang may have developed during the Vietnam War. Alternate spellings of the term include "clic" and "klik." The IPL also mentions that "klick" can be used to indicate a short distance rather than a specific distance.