heap vs collection

heap and collection both are nouns.

Word	Noun	Adjective	Verb	Adverb
heap	Yes	No	Yes	No
collection	Yes	No	No	No

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

Other hypernyms of heap include accumulation, aggregation, assemblage.

heap (noun)	collection (noun)
a car that is old and unreliable	the act of gathering something together
a collection of objects laid on top of each other	a publication containing a variety of works
(often followed by `of') a large number or amount or extent	request for a sum of money
	several things grouped together or considered as a whole