world power vs major power

world power and major power both are nouns.

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

As nouns, world power and major power are synonyms defined as:

world power and major power: a state powerful enough to influence events throughout the world

Other synonyms of world power include great power, power, superpower.

world power (noun)	major power (noun)
a state powerful enough to influence events throughout the world	a state powerful enough to influence events throughout the world