blowhole

blowhole
    n 1: the spiracle of a cetacean located far back on the skull
    2: a hole for the escape of gas or air [syn: {vent}, {venthole},
       {vent-hole}, {blowhole}]
    

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]
    

75 Moby Thesaurus words for "blowhole":
      air duct, air hole, air passage, air shaft, air tube, airway,
      armhole, avenue, breathing hole, bullet-hole, bunghole, channel,
      chute, cringle, deadeye, debouch, door, egress, emunctory, escape,
      estuary, exhaust, exit, eye, eyelet, floodgate, flume, gasket,
      grommet, guide, keyhole, knothole, loop, loophole, louver,
      louverwork, manhole, mousehole, naris, nostril, opening, out,
      outcome, outfall, outgate, outgo, outlet, peephole, pigeonhole,
      pinhole, placket, placket hole, pore, port, porthole, punch-hole,
      sally port, shaft, sluice, spilehole, spiracle, spout, tap,
      touchhole, transom, vent, ventage, venthole, ventiduct,
      ventilating shaft, ventilator, vomitory, way out, weir,
      wind tunnel