broom closet

noun2

1. •
   (US) A closet in which cleaning materials and associated equipment, such as brooms, are stored.

   • The backup team would be crouched in some tiny broom closet, with sweat rolling down their faces and their backs growing stiffer, and the jackrollers would just walk by. — 1988
2. •
   (humorous, figurative) The metaphorical place in which a Wiccan's religious identity is hidden.