break of the day vs break of day

break of the day and break of day both are nouns.

Word	Noun	Adjective	Verb	Adverb
break of the day	Yes	No	No	No
break of day	Yes	No	No	No

As nouns, break of the day and break of day are synonyms defined as:

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

break of the day (noun)	break of day (noun)
the first light of day	the first light of day