closet

From Middle English closet, borrowed from Old French closet, itself built from clos ("private space") plus the diminutive suffix -et, going back to Latin clausum. It's essentially close + -et.

In French, this word was used only for small open-air enclosures — a fenced-off bit of outdoor space, not a room. English took the word and moved it indoors, applying it to small private rooms and, eventually, the enclosed storage spaces we call closets today.

It shares its root with the English word close, both tracing back to Latin clausum, meaning shut or enclosed.