Source : Webster's Revised Unabridged Dictionary (1913)

Peacock \Pea"cock`\, n. [OE. pecok. Pea- in this word is from
   AS. pe['a], p[=a]wa, peacock, fr. L. pavo, prob. of Oriental
   origin; cf. Gr. ?, ?, Per. t[=a]us, t[=a]wus, Ar. t[=a]wu?s.
   See {Cock} the bird.]
   1. (Zo["o]l.) The male of any pheasant of the genus {Pavo},
      of which at least two species are known, native of
      Southern Asia and the East Indies.

   Note: The upper tail coverts, which are long and capable of
         erection, are each marked with a black spot bordered by
         concentric bands of brilliant blue, green, and golden
         colors. The common domesticated species is {Pavo
         cristatus}. The Javan peacock ({P. muticus}) is more
         brilliantly colored than the common species.

   2. In common usage, the species in general or collectively; a
      peafowl.

   {Peacock butterfly} (Zo["o]l.), a handsome European butterfly
      ({Hamadryas Io}) having ocelli like those of peacock.

   {Peacock fish} (Zo["o]l.), the European blue-striped wrasse
      ({Labrus variegatus}); -- so called on account of its
      brilliant colors. Called also {cook wrasse} and {cook}.

   {Peacock pheasant} (Zo["o]l.), any one of several species of
      handsome Asiatic pheasants of the genus {Polyplectron}.
      They resemble the peacock in color.