Yes, dawn is a noun, and it describes the morning sun rising in the east.
No. Noonday is another word.
noon
Noon
One option is "afternoon".
One option is "afternoon".
No the word "midday" is not hyphenated.
It would be am, as it is in the morning, before midday.
dawn
dawn
Dawn
Daybreak
day
Daybreak, sunrise, sunup.
daybreak