'Blowhole' definitions:

Definition of 'blowhole'

From: WordNet
noun
The spiracle of a cetacean located far back on the skull
noun
A hole for the escape of gas or air [syn: vent, venthole, vent-hole, blowhole]

Definition of 'Blowhole'

From: GCIDE
  • Blowhole \Blow"hole`\, n.
  • 1. A cavern in a cliff, at the water level, opening to the air at its farther extremity, so that the waters rush in with each surge and rise in a lofty jet from the extremity. [1913 Webster]
  • 2. A nostril or spiracle in the top of the head of a whale or other cetacean. [1913 Webster]
  • Note: There are two spiracles or blowholes in the common whales, but only one in sperm whales, porpoises, etc. [1913 Webster]
  • 3. A hole in the ice to which whales, seals, etc., come to breathe. [1913 Webster]
  • 4. (Founding) An air hole in a casting. [1913 Webster]