North America vs aggregation

North America and aggregation both are nouns.

Word	Noun	Adjective	Verb	Adverb
North America	Yes	No	No	No
aggregation	Yes	No	No	No

As nouns, aggregation is a hypernym of North America; that is, aggregation is a word with a broader meaning than North America:

Other hypernyms of North America include accumulation, assemblage, collection.

North America (noun)	aggregation (noun)
the nations of the North American continent collectively	the act of gathering something together
a continent (the third largest) in the western hemisphere connected to South America by the Isthmus of Panama	several things grouped together or considered as a whole