Related Clues:
- Heating outlet
- Release issued from the Royal Opera House?
- Hole left by explosion
- Capital of Virginia
- Impact hole
- Hollow box rattles at first
- Outlet; slit in jacket
- Opening of a volcano
- Volcanic opening
- Opening check involves unspecified amount
- Large hole in box runs to the bottom
- Opening releasing gas
- Orifice
- Opening for air/gas
- Feature visible on the moon