trash heap vs junk pile

trash heap and junk pile both are nouns.

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

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

trash heap and junk pile: an accumulation of refuse and discarded matter

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

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