world power vs hegemon

world power and hegemon both are nouns.

Word	Noun	Adjective	Verb	Adverb
world power	Yes	No	No	No
hegemon	Yes	No	No	No

As nouns, hegemon is a hyponym of world power; that is, hegemon is a word with a more specific, narrower meaning than world power:

world power: a state powerful enough to influence events throughout the world
hegemon: a leading or paramount power

world power (noun)	hegemon (noun)
a state powerful enough to influence events throughout the world	a leading or paramount power