noun (n)

• the first light of day(noun.time)

  Synonym:
  aurora, break of day, break of the day, cockcrow, dawn, dawning, daybreak, first light, morning, sunrise, sunup
  Antonym:
  sundown, sunset
  

  source: wordnet30
• The beginning of the day, or first appearance of light; the dawn; hence, the beginning.(noun)

  source: webster1913