Source : Free On-Line Dictionary of Computing

Administration Management Domain
     
         (ADMD) An {X.400} {Message Handling System}
        {public service carrier}.  The ADMDs in all countries
        worldwide together provide the X.400 {backbone}.  Examples:
        {MCImail} and {ATTmail} in the U.S., {British Telecom}
        {Gold400mail} in the U.K.
     
        See also {PRMD}.
     
        [RFC 1208].
     
        (1997-05-07)