What does "sunup" mean?

The time of day when the sun appears above the eastern horizon.

What is a synonym for "sunup"?

Common synonyms include: dawn, daybreak, sunrise, aurora, aurora, break of day.

/ˈsʌnʌp/ noun

noun ·Uncommon ·Advanced level

Noun

1
The time of day when the sun appears above the eastern horizon. US, countable, uncountable
"“Shagbark, that was risky on your part; even where it lies it is much closer than I like, for we shall all have to see it in the morning.” “No, you won’t; it’ll be gone afore sunup.”"
2
the first light of day wordnet
3
The change in color of the sky at sunup. US, countable, uncountable

"Tom worked from sunup to sundown."

sun + up