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

C shell
csh

    (csh) The Unix command-line interpreter
   shell and script language by William Joy, originating
   from Berkeley Unix.

   Unix systems up to around Unix Version 7 only had one
   shell - the Bourne shell, sh.  Csh had better interactive
   features, notably command input history, allowing earlier
   commands to be recalled and edited (though it was still not as
   good as the VMS equivalent of the time).

   Presumably, csh's C-like syntax was intended to endear it
   to programmers but sadly it lacks some sh features which are
   useful for writing shell scripts so you need to know two
   different syntaxes for every shell construct.

   A plethora of different shells followed csh, e.g. tcsh,
   ksh, bash, rc, but sh and csh are the only ones which
   are provided with most versions of Unix.

   (1998-04-04)