coin collection vs accumulation

coin collection and accumulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
coin collection	Yes	No	No	No
accumulation	Yes	No	No	No

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

Other hypernyms of coin collection include aggregation, assemblage, collection.

coin collection (noun)	accumulation (noun)
the collection and study of money (and coins in particular)	the act of accumulating
a collection of coins	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