Central America vs aggregation

Central America and aggregation both are nouns.

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

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

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

Central America (noun)	aggregation (noun)
the nations of Central America collectively	the act of gathering something together
the isthmus joining North America and South America; extends from the southern border of Mexico to the northern border of Colombia	several things grouped together or considered as a whole