As used in the New Testament, signifies properly a storehouse (Luke 12:24), and hence a place of privacy and retirement (Matthew 6:6; Luke 12:3).

Noah Webster's New International Dictionary of the English Language

1. (n.) A small room or apartment for retirement; a room for privacy.

2. (n.) A small apartment, or recess in the side of a room, for household utensils, clothing, etc.

3. (v. t.) To shut up in, or as in, a closet; to conceal.

4. (v. t.) To make into a closet for a secret interview.