North America vs accumulation

North America and accumulation both are nouns.

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

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

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

North America (noun)	accumulation (noun)
the nations of the North American continent collectively	the act of accumulating
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
	(finance) profits that are not paid out as dividends but are added to the capital base of the corporation
	an increase by natural growth or addition