Definition of call letters

combination of letters assigned by the Federal Communications Commission that identify any broadcast station. The initial call letter is W for stations east of the Mississippi and K for all those west of the Mississippi. (There are a few exceptions to this rule, because some stations were licensed before FCC regulations came into being.) The additional letters may represent an abbreviation such as WABC (ABC representing American Broadcasting Company) or may form a word that describes or advertises the station's format, such as WNEW or WJOY. The FCC requires that all stations must identify themselves by their call letters on a regular schedule throughout the broadcast day as well as at the beginning and end of programming every day.