stack vs haystack

stack and haystack both are nouns.

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

As nouns, haystack is a hyponym of stack; that is, haystack is a word with a more specific, narrower meaning than stack:

Other hyponyms of stack include hayrick, rick.

stack (noun)	haystack (noun)
a large tall chimney through which combustion gases and smoke can be evacuated	a stack of hay
a storage device that handles data so that the next item to be retrieved is the item most recently stored (LIFO)
a list in which the next item to be removed is the item most recently stored (LIFO)
an orderly pile
(often followed by `of') a large number or amount or extent

stack (verb)	haystack (verb)
arrange in stacks
load or cover with stacks
arrange the order of so as to increase one's winning chances