Source : Free On-Line Dictionary of Computing

Internet Relay Chat
     
         (IRC) /I-R-C/, occasionally /*rk/ A
        {client-server} {chat} system of large (often worldwide)
        networks.  IRC is structured as networks of {Internet}
        {servers}, each accepting connections from {client} programs,
        one per user.
     
        The IRC community and the {Usenet} and {MUD} communities
        overlap to some extent, including both {hackers} and regular
        folks who have discovered the wonders of computer networks.
        Some {Usenet} jargon has been adopted on IRC, as have some
        conventions such as {emoticons}.  There is also a vigorous
        native jargon (see the entry for "{chat}").
     
        The largest and first IRC network is {EFNet}, with a smaller
        breakaway network called the {Undernet} having existed since
        1992, and dozens of other networks having appeared (and
        sometimes disappeared) since.
     
        See also {nick}, {bot}, {op}.
     
        {Yahoo's IRC index
        (http://www.yahoo.com/Computers_and_Internet/Internet/Chat/IRC/)}.
     
        (1998-01-25)