powder magazine vs storehouse

powder magazine and storehouse both are nouns.

Word	Noun	Adjective	Verb	Adverb
powder magazine	Yes	No	No	No
storehouse	Yes	No	No	No

As nouns, storehouse is a hypernym of powder magazine; that is, storehouse is a word with a broader meaning than powder magazine:

powder magazine: a storehouse (as a compartment on a warship) where weapons and ammunition are stored
storehouse: a depository for goods

Other hypernyms of powder magazine include depot, entrepot, storage, store.

powder magazine (noun)	storehouse (noun)
a storehouse (as a compartment on a warship) where weapons and ammunition are stored	a depository for goods