Source : Free On-Line Dictionary of Computing

PL/M
     
        Programming Language/Microcomputers.  MAA (later Digital
        Research) for Intel, 1972.  A very low level language
        incorporating ideas from PL/I, ALGOL and XPL.  Integrated
        macro processor.  Originally the implementation language for
        CP/M.  "PL/M-80 Programming Manual", Doc 98-268B, Intel 1976.
        "A Guide to PL/M Programming for Microcomputer Applications",
        D. McCracken, A-W 1978.  Versions: PL/M-80, PL/M-86, PL/M-286.