caller ID

Short definition from Wiktionary

Noun

1. 1
   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.
2. 2
   The service of providing such information, sometimes included in one's standard telephone contract and sometimes available for an extra fee.
3. 3
   Alternative form of caller ID.
4. 4
   Alternative form of caller ID.
5. 5
   Alternative form of caller ID.