Source : Webster's Revised Unabridged Dictionary (1913)

Clique \Clique\, n. [F., fr. OF. cliquer to click. See {Click},
   v. i.]
   A narrow circle of persons associated by common interests or
   for the accomplishment of a common purpose; -- generally used
   in a bad sense.

Clique \Clique\, v. i.
   To To associate together in a clannish way; to act with
   others secretly to gain a desired end; to plot; -- used with
   together.

Source : WordNet®

clique
     n : an exclusive circle of people with a common purpose [syn: {coterie},
          {ingroup}, {inner circle}, {pack}, {camp}]

Source : Free On-Line Dictionary of Computing

clique
     
         A {maximal} {totally connected} {subgraph}.
        Given a {graph} with {nodes} N, a clique C is a {subset} of N
        where every node in C is directly connected to every other
        node in C (i.e. C is totally connected), and C contains all
        such nodes (C is maximal).  In other words, a clique contains
        all, and only, those nodes which are directly connected to all
        other nodes in the clique.
     
        [Is this correct?]
     
        (1996-09-22)