Source : Webster's Revised Unabridged Dictionary (1913)

Cockcrow \Cock"crow\, Cockcrowing \Cock"crow`ing\, n.
   The time at which cocks first crow; the early morning.

Source : WordNet®

cockcrow
     n : the first light of day; "we got up before dawn"; "they
         talked until morning" [syn: {dawn}, {dawning}, {morning},
          {aurora}, {first light}, {daybreak}, {break of day}, {break
         of the day}, {dayspring}, {sunrise}, {sunup}] [ant: {sunset}]