blowhole Meaning, Definition & Usage

  1. noun the spiracle of a cetacean located far back on the skull
  2. noun a hole for the escape of gas or air
    vent; venthole; vent-hole.

WordNet

Blow"hole` noun
Definitions
  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.
  2. A nostril or spiracle in the top of the head of a whale or other cetacean. ✍ There are two spiracles or blowholes in the common whales, but only one in sperm whales, porpoises, etc.
  3. A hole in the ice to which whales, seals, etc., come to breathe.
  4. (Founding) An air hole in a casting.

Webster 1913