compost heap vs cumulus

compost heap and cumulus both are nouns.

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

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

compost heap: a heap of manure and vegetation and other organic residues that are decaying to become compost
cumulus: a collection of objects laid on top of each other

Other hypernyms of compost heap include agglomerate, cumulation, heap, mound, pile.

compost heap (noun)	cumulus (noun)
a heap of manure and vegetation and other organic residues that are decaying to become compost	a collection of objects laid on top of each other
	a globular cloud

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