An aperture in the upper rocks of a cliff or on the cliff’s head which is connected to a cave or cavity at the cliff’s base in such a way as to create a flow of air between the two openings. In some cases waves entering the cave at the base of the cliff act like pistons to push air and water at high pressure through the aperture which can spout like a whale.
Etymology
A hole that blows
Example locations
Wheal Coates
Chapel Porth, Cornwall