It means "kilometer" and the correct spelling is "klicks" with a "k" Hope this helps.^^

Kilometres

"Kilometers." In the United States, it's military usage (like the use of 24-hour time). The word is intentionally designed to be spoken quickly, and understood in noisy environments or over a bad connection. It's spelled "klick" so that it will begin with a "k," like "kilometer." It isn't used in everyday life by non-military people. Civilians stick to the U.S. customary distance unit, miles. It's like the use of the "phonetic alphabet" ("Alpha, Bravo, Charlie, Delta, Echo" instead of "A, B, C, D, E") or distorting the pronunciation of "nine" as "niner.")