The Free On-line Dictionary of Computing (19 January 2023):

Bourne shell

    (sh) The original command-line
   interpreter shell and script language for Unix, written
   by S.R. Bourne of Bell Laboratories in 1978.  sh was
   superseded for interactive use by the Berkeley C shell,
   csh but is still widely used for writing shell scripts.

   There were even earlier shells, see glob.  [Details?]

   bash is a widely used reimplementation of sh.  ash is a
   Bourne shell clone.

   ["Unix Time-Sharing System: The Unix Shell", S.R. Bourne,
   Bell Sys Tech J 57(6):1971-1990, Jul 1978].

   (2020-05-23)