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).