The Jargon File (version 4.4.7, 29 Dec 2003):

control-C
 vi.

    1. ?Stop whatever you are doing.? From the interrupt character used on many
    operating systems to abort a running program. Considered silly.

    2. interj. Among BSD Unix hackers, the canonical humorous response to ?Give
    me a break!?


The Free On-line Dictionary of Computing (30 December 2018):

control-C
End Of Text
ETX

    (Or ETX, End of Text) The ASCII character with
   code 3.

   Control-C is the interrupt character used in the
   command-line interface of many operating systems,
   including Unix and MS-DOS, to force the currently running
   program to stop and return control to the user.

   [Jargon File]

   (1995-03-16)