{i} vent for the escape of gas or air; spiracle of a whale or another cetacean located far back on the head; hole in the ice to which animals (such as whales, seals, etc.) come to breathe
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
[ 'blO ] (verb.) before 12th century. Middle English, from Old English blAwan; akin to Old High German blAen to blow, Latin flare, Greek phallos penis.