means A tall cabinet or built-in closet for storing clothes, or by extension the entire collection of garments a person owns.

from From Old French 'warderobe' (in the northern dialect) or 'garderobe' — literally 'guard the robe,' from 'warder/garder' (to keep, guard) plus 'robe' (garment). It entered English in the medieval period as a place to safeguard one's clothing. Curiously, the same word once also named a private privy or toilet chamber, since both were small rooms tucked off the main hall — a humbler genealogy than C.S. Lewis would let on.