Zetalisp

from The Free On-line Dictionary of Computing (8 July 2008)

ZetaLisp

   <language> The {Maclisp} dialect used on the {LISP Machine}.
   The many extensions to Maclisp include {vectors}, {closures},
   {flavors}, {stack groups}, {locatives}, and {invisible
   pointers}.  Currently supported by {Lisp Machines, Inc.} and
   {Symbolics}.

   ["LISP Machine Manual", D. Weinreb and D. Moon, MIT AI Lab,
   1981].

   (1997-03-18)