load up vs stack

load up is not a noun while stack is a noun.

Word	Noun	Adjective	Verb	Adverb
load up	No	No	Yes	No
stack	Yes	No	Yes	No

As verbs, stack is a hyponym of load up; that is, stack is a word with a more specific, narrower meaning than load up:

Other hyponyms of load up include load down, pack, bomb up, overcharge, overload, surcharge, reload.

load up (noun)	stack (noun)
	a large tall chimney through which combustion gases and smoke can be evacuated
	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

load up (verb)	stack (verb)
fill or place a load on	arrange in stacks
	load or cover with stacks
	arrange the order of so as to increase one's winning chances