nighttime vs twenty-four hour period

nighttime and twenty-four hour period both are nouns.

Word	Noun	Adjective	Verb	Adverb
nighttime	Yes	No	No	No
twenty-four hour period	Yes	No	No	No

nighttime (noun)	twenty-four hour period (noun)
the time after sunset and before sunrise while it is dark outside	time for Earth to make a complete rotation on its axis