deposit box vs strongbox

deposit box and strongbox both are nouns.

Word	Noun	Adjective	Verb	Adverb
deposit box	Yes	No	No	No
strongbox	Yes	No	No	No

As nouns, strongbox is a hypernym of deposit box; that is, strongbox is a word with a broader meaning than deposit box:

deposit box: a fireproof metal strongbox (usually in a bank) for storing valuables
strongbox: a strongly made box for holding money or valuables; can be locked

Other hypernyms of deposit box include deedbox.

deposit box (noun)	strongbox (noun)
a fireproof metal strongbox (usually in a bank) for storing valuables	a strongly made box for holding money or valuables; can be locked