compost heap vs heap

compost heap and heap both are nouns.

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

As nouns, heap is a hypernym of compost heap; that is, heap 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
heap: a collection of objects laid on top of each other

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

compost heap (noun)	heap (noun)
a heap of manure and vegetation and other organic residues that are decaying to become compost	a car that is old and unreliable
	a collection of objects laid on top of each other
	(often followed by `of') a large number or amount or extent