Definition of blowhole in US English:



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

    • ‘A calf will hump up onto the back of the sleeping mother, breach onto her, cover her blowhole with his tail.’
    • ‘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.’
    • ‘When they dive, muscles close the blowhole and their ribcage collapses to keep air bubbles from forming in the bloodstream.’
    • ‘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.’
    • ‘One of the whales spouted a cloud of mist from its blowhole.’
    1. 1.1 A hole in ice to which seals, whales, and other aquatic animals come to breathe.
      • ‘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.’
      • ‘They will sit by a seal blowhole for hours, waiting, until the animal surfaces.’
      • ‘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.’
      • ‘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.’
      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.
      • ‘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.’
      • ‘This electrical power generating system is applicable in any location where wave action in blowholes produces compressed air.’
      • ‘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.’
      • ‘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.
      • ‘Producers of iron castings sometimes are confronted by a rash of blowhole or pinhole defects that take time and money to correct.’
      • ‘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.’
      • ‘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.’
      • ‘Unlike a casting, a spun part that requires further machining will not be scrapped by a hidden blowhole or inclusion.’
      • ‘The vacuum eliminates blowhole residue completely and enhances metal quality.’