- an air or gas vent, especially one to carry off fumes from a tunnel, underground passage, etc.
- either of two nostrils or spiracles, or a single one, at the top of the head in whales and other cetaceans, through which they breathe.
- a hole in the ice to which whales or seals come to breathe.
- a defect in a casting or ingot caused by the escape of gas.
- a hole in a sea cliff or coastal terrace through which columns of spray are jetted upward.
- the nostril, paired or single, of whales, situated far back on the skull
- a hole in ice through which whales, seals, etc, breathe
- a vent for air or gas, esp to release fumes from a tunnel, passage, etc
- a hole emitting gas or steam in a volcanic region
- a bubble-like defect in an ingot resulting from gas being trapped during solidification
- a hole in a cliff top leading to a sea cave through which air is forced by the action of the sea
