[kaw-ler] 
| a telephone service that allows a subscriber to identify a caller before answering by displaying the caller's telephone number on a small screen. |
| call·er ID (kô'lər) n. A telephone service that provides for subscribers the name and telephone number of a caller, which appear on a display as the call is being received. |
Caller ID communications
(CID) A short piece of text transmitted by some telephone systems describing the origin of a call, e.g. the name of the caller. Some telephone handsets can display this. A computer telephony integration system might use it to trigger actions on the callee's computer such as looking up the caller in a database and displaying their details on screen.
There may also be a separate "caller id number" giving the telephone number of the originator of the call.
(2008-04-30)