Related Clues:

• Heating outlet
• Ventilation conduit
• Release issued from the Royal Opera House?
• Quickly avoided noise in the Tube
• Outlet; slit in jacket
• French noble heading for the channel
• Opening of a volcano
• Passage for cables etc.
• Volcanic opening
• Opening check involves unspecified amount
• The Eve of St - is a narrative poem by Keats
• Opening releasing gas
• Orifice
• Tube for air, cables, etc
• Opening for air/gas