MACLISP
From Computer History Wiki
Influential dialect of LISP. Developed initially as the standalone PDP-6 LISP at Project MAC, then moved to ITS and renamed MACLISP somewhere along the way. Later ported to TOPS-10, WAITS, TOPS-20, and Multics.
Descendants include Lisp Machine Lisp, Common Lisp, and Emacs Lisp.