store vs powder store

store and powder store both are nouns.

Word	Noun	Adjective	Verb	Adverb
store	Yes	No	Yes	No
powder store	Yes	No	No	No

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

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

store (noun)	powder store (noun)
a mercantile establishment for the retail sale of goods or services	a storehouse (as a compartment on a warship) where weapons and ammunition are stored
a depository for goods
an electronic memory device
a supply of something available for future use

store (verb)	powder store (verb)
keep or lay aside for future use
find a place for and put away for storage