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

Classic C
 /klas'ik C/, n.

    [a play on ?Coke Classic?] The C programming language as defined in the
    first edition of K&R, with some small additions. It is also known as ?K&R
    C?. The name came into use while C was being standardized by the ANSI X3J11
    committee. Also ?C Classic?.

    An analogous construction is sometimes applied elsewhere: thus, ?X
    Classic?, where X = Star Trek (referring to the original TV series) or X =
    PC (referring to IBM's ISA-bus machines as opposed to the PS/2 series).
    This construction is especially used of product series in which the newer
    versions are considered serious losers relative to the older ones.


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

K&R C
Classic C

    (C Classic) The C programming language as defined
   in the first edition of K&R, with some small additions.  The
   name "C Classic", a play on "Coke Classic", came into use
   while ANSI C was being standardised by the ANSI X3J11
   committee.

   See also classic.

   [Jargon File]

   (2006-09-26)