twenty-four hours vs daytime

twenty-four hours and daytime both are nouns.

Word	Noun	Adjective	Verb	Adverb
twenty-four hours	Yes	No	No	No
daytime	Yes	No	No	No

twenty-four hours (noun)	daytime (noun)
time for Earth to make a complete rotation on its axis	the time after sunrise and before sunset while it is light outside