Source : Free On-Line Dictionary of Computing

PCI Mezzanine Card
     
         (PMC) A family of low profile {mezzanine} cards for
        {VMEbus}, {Futurebus+}, desktop computers and other computer
        systems with logical and electrical layers based on the
        {Peripheral Component Interconnect} (PCI) specification.  PMC
        is defined in {IEEE} P1386.1 and follows the {Common Mezzanine
        Card} (CMC) mechanical specification.
     
        PCI2.0 defines a 4.2 inch by 12.3 inch board that plugs
        perpendicularly into a {mother board}.
     
        (1994-10-06)