Source : Webster's Revised Unabridged Dictionary (1913)

Cock \Cock\, n. [AS. coc; of unknown origin, perh. in imitation
   of the cry of the cock. Cf. {Chicken}.]
   1. The male of birds, particularly of gallinaceous or
      domestic fowls.

   2. A vane in the shape of a cock; a weathercock.

            Drenched our steeples, drowned the cocks! --Shak.

   3. A chief man; a leader or master. [Humorous]

            Sir Andrew is the cock of the club, since he left
            us.                                   --Addison.

   4. The crow of a cock, esp. the first crow in the morning;
      cockcrow. [Obs.]

            He begins at curfew, and walks till the first cock.
                                                  --Shak.

   5. A faucet or valve.

   Note: Jonsons says, ``The handly probably had a cock on the
         top; things that were contrived to turn seem anciently
         to have had that form, whatever was the reason.''
         Skinner says, because it used to be constructed in
         forma crit[ae] galli, i.e., in the form of a cock's
         comb.

   6. The style of gnomon of a dial. --Chambers.

   7. The indicator of a balance. --Johnson.

   8. The bridge piece which affords a bearing for the pivot of
      a balance in a clock or watch. --Knight.

   {Ball cock}. See under {Ball}.

   {Chaparral cock}. See under {Chaparral}.

   {Cock and bull story}, {an extravagant}, boastful story; a
      canard.

   {Cock of the plains} (Zo["o]l.) See {Sage cock}.

   {Cock of the rock} (Zo["o]l.), a South American bird
      ({Rupicola aurantia}) having a beautiful crest.

   {Cock of the walk}, a chief or master; the hero of the hour;
      one who has overcrowed, or got the better of, rivals or
      competitors.

   {Cock of the woods}. See {Capercailzie}.

Source : WordNet®

cock of the rock
     n 1: bird of the Andes similar to Rupicola rupicola [syn: {Rupicola
          peruviana}]
     2: tropical bird of northern South America the male having
        brilliant red or orange plumage and an erectile disklike
        crest [syn: {Rupicola rupicola}]