hour vs twenty-four hours

hour and twenty-four hours both are nouns.

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

hour (noun)	twenty-four hours (noun)
distance measured by the time taken to cover it	time for Earth to make a complete rotation on its axis
a period of time equal to 1/24th of a day
clock time
a special and memorable period