"sunup" in the noun sense
1. dawn, dawning, morning, aurora, first light, daybreak, break of day, break of the day, dayspring, sunrise, sunup, cockcrow
the first light of day
"we got up before dawn"
"they talked until morning"
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License