'armary' originates from Latin, specifically the word 'armarium', where 'arma' meant 'arms' or 'weapons' and '-arium' was a suffix denoting a place or receptacle.

'armarium' passed into Old French as 'armarie' or Anglo-French forms and then into Middle English as 'armary'; later variants produced the modern spellings 'armory' (US) and 'armoury' (UK), while 'armary' remained an archaic or rare form.

Initially it referred broadly to a chest or cupboard for storing items (including books or clothes), but over time the sense narrowed to specifically mean a place for storing arms and military equipment.