junk pile vs junk heap

junk pile and junk heap both are nouns.

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

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

Other synonyms of junk pile include garbage heap, refuse heap, rubbish heap, scrapheap, trash heap, trash pile.

junk pile (noun)	junk heap (noun)
an accumulation of refuse and discarded matter	an accumulation of refuse and discarded matter