As used in the New Testament, signifies properly a storehouse (Luke 12: 24), and hence a place of privacy and retirement (Matt. 6:6; Luke 12:3).
Closet
1 verse
Matthew
Matthew 6:6
But thou, when thou prayest, enter into thy closet, and when thou hast shut thy door, pray to thy Father which is in secret; and thy Father which seeth in secret shall reward thee openly.
From Easton's Bible Dictionary
Matthew George Easton, 1897