Definition of "CID"

caller identification; a feature that identifies the phone number of the caller.  examples

Abbreviation of combat identification. (compare IFF)  examples

Acronym of center/centre instrument display.  examples

Initialism of criminal investigation/investigative division/department.  examples

(British, law enforcement, initialism) Scotland Yard Criminal Investigation Department  examples

(US, military, law enforcement, initialism) U.S. Army Criminal Investigation Command

(US, military, law enforcement, initialism) Former name of NCIS. (Naval Criminal Investigation Division)