Definition of blowhole in US English:



  • 1The nostril of a whale or dolphin on the top of its head.

    • ‘They are surrounded by crowds of people stroking and patting them often near sensitive areas such as their blowholes and they become obese through uncontrolled feeding.’
    • ‘While the rest of us stood agog as the spray from the whales' blowholes misted over the deck, three divers managed to slip into the water.’
    • ‘One of the whales spouted a cloud of mist from its blowhole.’
    • ‘A calf will hump up onto the back of the sleeping mother, breach onto her, cover her blowhole with his tail.’
    • ‘When they dive, muscles close the blowhole and their ribcage collapses to keep air bubbles from forming in the bloodstream.’
    1. 1.1 A hole in ice to which seals, whales, and other aquatic animals come to breathe.
      • ‘Polar bears will stand or lie by the seal’s blowhole in the ice for hours; they may swim towards seals resting on the ice flows with only their nose showing above the water.’
      • ‘The bears wait and watch at the seal's blowhole, not moving, perhaps hiding their black noses behind the ice.’
      • ‘Soon you come across a blowhole forming a vertical shaft 1.5m in diameter that leads to the surface.’
      • ‘A burly man raises a stick with a hook on the end to strike a baby seal as it surfaces from a blowhole in the ice.’
      • ‘They will sit by a seal blowhole for hours, waiting, until the animal surfaces.’
      outlet, inlet, opening, aperture, vent hole, hole, gap, orifice, space, cavity, cleft, slit, pore, port
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    2. 1.2 A vent for air or smoke in a tunnel or other structure.
      • ‘Tunnels and Caves is another popular site, starting and finishing through a blowhole that leads to an underwater playground of caves and tunnels, where bubbles escape through volcanic fissures.’
      • ‘This electrical power generating system is applicable in any location where wave action in blowholes produces compressed air.’
      • ‘This can probably be attributed to the top blowhole wicking away the rising hot air.’
      • ‘This vent area is not your standard side mounted blowhole.’
      • ‘It has blowholes and lava tubes, the wettest spot on earth, and the nation's only royal palace.’
      vent, vent hole, way out, exit, egress
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    3. 1.3 A cavity in a metal casting, produced by the escape of air through the liquid metal.
      • ‘Unlike a casting, a spun part that requires further machining will not be scrapped by a hidden blowhole or inclusion.’
      • ‘The invention provides an apparatus and a method for reducing the volume of risers, and for the possibility of reducing shrinkage, blowhole and porosity in shaped gravity casting.’
      • ‘The vacuum eliminates blowhole residue completely and enhances metal quality.’
      • ‘A third fault or defect type is blowhole formation due to air and gas inclusions, which arise during casting, but mainly in the phase just before the end of casting.’
      • ‘Producers of iron castings sometimes are confronted by a rash of blowhole or pinhole defects that take time and money to correct.’