As a noun, it means the time of sunrise. It's a bit more specific than just 'early morning'. It can also be used more figuratively, such as 'the dawn of a new civilisation', meaning the start of it. As a verb, 'dawn on' is a passive version of 'come to understand' - "it finally dawned on me that she didn't love me". "I'm just waiting for that fact to dawn on you".

early morning

Oi Enzo. Eu acho que “dawn” significa amanhecer

Your word order isn't very natural: What does the expression "Dawn" mean?