dozens vs piles

dozens and piles both are nouns.

Word	Noun	Adjective	Verb	Adverb
dozens	Yes	No	No	No
piles	Yes	No	No	No

As nouns, dozens and piles are synonyms defined as:

Other synonyms of dozens include gobs, heaps, lashings, loads, lots, oodles, rafts, scads, scores, slews, stacks, tons, wads.

dozens (noun)	piles (noun)
a large number or amount	a large number or amount
	venous swelling external or internal to the anal sphincter