dawn noun definition in The sun and the moon topic from the Oxford Advanced Learner's Dictionary

dawn

 noun: The sun and the moon topic
[uncountable, countable] the time of day when light first appears They start work at dawn. It's almost dawn. We arrived in Sydney as dawn broke (= as the first light could be seen). I woke up just before dawn. summer’s early dawns He works from dawn till dusk (= from morning till night). The plane took off, leaving London behind in a blue-grey dawn.