King James Bible Dictionary

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).

Used as a place for prayer
Matthew 6:6

CLOSET, noun s as z.

1. A small room or apartment for retirement; any room for privacy.

When thou prayest, inter into thy closet Matthew 6:6.

2. An apartment for curiosities or valuable things.

3. A small close apartment or recess in the side of a room for repositing utensils and furniture.

CLOSET, verb transitive s as z. To shut up in a closet; to conceal; to take into a private apartment for consultation.

CLOSETED, participle passive s as z. Shut up in a closet; concealed.

CLOSETING, participle present tense s as z. Shutting up in a private room; concealing.

CLOSET-SIN, noun Sin committed in privacy.