first light vs sunrise

first light and sunrise both are nouns.

Word	Noun	Adjective	Verb	Adverb
first light	Yes	No	No	No
sunrise	Yes	Yes	No	No

As nouns, first light and sunrise are synonyms defined as:

Other synonyms of first light include aurora, break of day, break of the day, cockcrow, dawn, dawning, daybreak, dayspring, morning, sunup.

first light (noun)	sunrise (noun)
the first light of day	the daily event of the sun rising above the horizon
	atmospheric phenomena accompanying the daily appearance of the sun
	the first light of day

first light (adjective)	sunrise (adjective)
	of an industry or technology; new and developing