Source : Free On-Line Dictionary of Computing

NetBEUI
     
        {NetBIOS} Extended User Interface.  The network transport
        {protocol} used by all of {Microsoft}'s network systems and
        {IBM}'s {LAN Server} based systems.
     
        NetBEUI is often confused with {NetBIOS}.  NetBIOS is the
        {applications programming interface} and NetBEUI is the
        transport protocol.