Source : Webster's Revised Unabridged Dictionary (1913)

Daybreak \Day"break`\ (d[=a]"br[=a]k`), n.
   The time of the first appearance of light in the morning.

Source : WordNet®

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