Caller I.D.

Noun

caller ID (countable and uncountable, plural caller IDs)

1. (countable) The telephone number and/or name of the originator of an incoming telephone call, displayed on the screen of the telephone or other electronic device receiving the call.
   • I've been trying out some of the new watches that display caller IDs, text messages, Twitter and news feeds, and the weather, too.2012 May 19, Anne Eisenberg, “It’s Not Dick Tracy’s, but It Can Screen Your Messages”, in New York Times, retrieved 20 May 2014
2. (uncountable) The service of providing such information, sometimes included in one's standard telephone contract and sometimes available for an extra fee.
   • The new phone service known as Caller I.D. is a double-edged sword: it protects the privacy of some people, but at the expense of others.1991 November 11, Richard Lacayo, “Now We've Really Got Your Number”, in Time, retrieved 20 May 2014