(military) A call sign assigned in accordance with the provisions of the International Telecommunications Union to identify a radio station. The nationality of the radio station is identified by the first or the first two characters. (When used in visual signaling, international call signs are referred to as “signal letters.”)

(military) A call sign that represents all stations within a net.

(military) A call sign that identifies a tactical command or tactical communication facility.

(military) Any call sign which represents two or more facilities, commands, authorities, or units. The collective call sign for any of these includes the commander thereof and all subordinate commanders therein.

(military) A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these.

Military call signs are call signs (or callsigns) or specialized form of nickname assigned as unique identifiers to military communications.

Call Sign Extortion 17: The Shoot-Down of SEAL Team Six is a 2015 non-fiction expose, written by best-selling author and former U.S. Navy JAG Officer Don Brown, about the 2011 Chinook shootdown in Afghanistan of a United States Boeing CH-47 Chinook helicopter.

An aviator call sign or aviator callsign is a call sign given to a military pilot, flight officer, and even some enlisted aviators.

Maritime call signs are call signs assigned as unique identifiers to ships and boats.