South America vs aggregation

South America and aggregation both are nouns.

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

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

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

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