stack vs pile

stack and pile both are nouns.

Word	Noun	Adjective	Verb	Adverb
stack	Yes	No	Yes	No
pile	Yes	No	Yes	No

As nouns, pile is a hypernym of stack; that is, pile is a word with a broader meaning than stack:

Other hypernyms of stack include agglomerate, cumulation, cumulus, heap, mound.

As nouns, stack and pile are synonyms defined as:

stack and pile: (often followed by `of') a large number or amount or extent

As verbs, stack and pile are synonyms defined as:

Other synonyms of stack include heap.

stack (noun)	pile (noun)
a large tall chimney through which combustion gases and smoke can be evacuated	a nuclear reactor that uses controlled nuclear fission to generate energy
a storage device that handles data so that the next item to be retrieved is the item most recently stored (LIFO)	battery consisting of voltaic cells arranged in series; the earliest electric battery devised by Volta
a list in which the next item to be removed is the item most recently stored (LIFO)	the yarn (as in a rug or velvet or corduroy) that stands up from the weave
an orderly pile	a column of wood or steel or concrete that is driven into the ground to provide support for a structure
(often followed by `of') a large number or amount or extent	fine soft dense hair (as the fine short hair of cattle or deer or the wool of sheep or the undercoat of certain dogs)
	a collection of objects laid on top of each other
	a large sum of money (especially as pay or profit)
	(often followed by `of') a large number or amount or extent

stack (verb)	pile (verb)
arrange in stacks	arrange in stacks
load or cover with stacks	place or lay as if in a pile
arrange the order of so as to increase one's winning chances	press tightly together or cram