means The act of keeping things somewhere safe for later use, or the space set aside for that purpose.

from From 'store,' which entered English through Old French 'estorer' (to build, furnish, supply), tracing back to Latin 'instaurare' (to restore or renew) — a cousin of 'restore.' The '-age' suffix, also from French, turns the verb into the abstract business of doing it. So a word once about furnishing and renewing slowly settled into meaning the place where things sit doing neither.