DuckCorp Dico

Found one definition

1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   METAL
      1. Mega-Extensive Telecommunications Applications Language.
      BBS language for PRODOS 8 on Apple II.
      2. The syntax-definition formalism of the Mentor system.
      Metal specifications are compiled to specifications for a
      scanner/parser generator such as Lex/Yacc.  "Metal: A
      Formalism to Specify Formalisms", G.  Kahn et al, Sci Comp
      Prog 3:151-188 (1983).