Source : Webster's Revised Unabridged Dictionary (1913)

Socket \Sock"et\, n. [OE. soket, a dim. through OF. fr. L.
   soccus. See {Sock} a covering for the foot.]
   1. An opening into which anything is fitted; any hollow thing
      or place which receives and holds something else; as, the
      sockets of the teeth.

            His eyeballs in their hollow sockets sink. --Dryden.

   2. Especially, the hollow tube or place in which a candle is
      fixed in the candlestick.

            And in the sockets oily bubbles dance. --Dryden.

   {Socket bolt} (Mach.), a bolt that passes through a thimble
      that is placed between the parts connected by the bolt.

   {Socket chisel}. Same as {Framing chisel}. See under
      {Framing}.

   {Socket pipe}, a pipe with an expansion at one end to receive
      the end of a connecting pipe.

   {Socket pole}, a pole armed with iron fixed on by means of a
      socket, and used to propel boats, etc. [U.S.]

   {Socket wrench}, a wrench consisting of a socket at the end
      of a shank or rod, for turning a nut, bolthead, etc., in a
      narrow or deep recess.

Source : WordNet®

socket
     n 1: a bony hollow into which a structure fits
     2: receptacle where something (a pipe or probe or end of a
        bone) is inserted
     3: a receptacle into which an electric device can be inserted

Source : Free On-Line Dictionary of Computing

socket
     
         The {Berkeley Unix} mechansim for creating a
        virtual connection between processes.  Sockets interface
        {Unix}'s {standard I/O} with its {network} communication
        facilities.  They can be of two types, stream (bi-directional)
        or {datagram} (fixed length destination-addressed messages).
        The socket library function socket() creates a communications
        end-point or socket and returns a {file descriptor} with which
        to access that socket.  The socket has associated with it a
        socket address, consisting of a {port} number and the local
        host's network address.
     
        {Unix manual page}: socket(2).
     
        (1995-01-31)