blowhole
noun
Definitions
The spiracle, on the top of the head, through which cetaceans breathe.
A vent for the escape of gas.
A top-facing opening to a cavity in the ground very near an ocean's shore, leading to a marine cave from which wave water or bursts of air are expelled.
An unintended cavity filled with air in a casting product.
verb
Definitions
To fill or be filled with air in an unintended cavity.