compost pile vs compost heap

compost pile and compost heap both are nouns.

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

As nouns, compost pile and compost heap are synonyms defined as:

compost pile and compost heap: a heap of manure and vegetation and other organic residues that are decaying to become compost

compost pile (noun)	compost heap (noun)
a heap of manure and vegetation and other organic residues that are decaying to become compost	a heap of manure and vegetation and other organic residues that are decaying to become compost