cumulus vs heap

cumulus and heap both are nouns.

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

As nouns, cumulus and heap are synonyms defined as:

Other synonyms of cumulus include agglomerate, cumulation, mound, pile.

cumulus (noun)	heap (noun)
a collection of objects laid on top of each other	a car that is old and unreliable
a globular cloud	a collection of objects laid on top of each other
	(often followed by `of') a large number or amount or extent

cumulus (adjective)	heap (adjective)
of or related to cumulous clouds