WordWeight : Weighing the Words

Pronunciation : Blow"hole`
Part of Speech : n.
Definition : 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.

Note: 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)

Defn: An air hole in a casting.
Source : Webster's Unabridged Dictionary, 1913