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1. Zoology A respiratory aperture, especially:
a. Any of several tracheal openings in the exoskeleton of an insect, spider, or other terrestrial arthropod.
b. A small respiratory opening behind the eye of most sharks and rays and certain other fishes.
c. The blowhole of a cetacean.
2. An aperture or opening through which air is admitted and expelled.
[Middle English, from Latin spīrāculum, from spīrāre, to breathe.]
spi·rac′u·lar (spī-răk′yə-lər, spĭ-) adj.
1. (Zoology) any of several paired apertures in the cuticle of an insect, by which air enters and leaves the trachea
2. (Zoology) a small paired rudimentary gill slit just behind the head in skates, rays, and related fishes
3. (Zoology) any similar respiratory aperture, such as the blowhole in whales
4. (Geological Science) geology a protrusion of sediment into a lava flow, formed by the explosive transition of water into steam
[C14 (originally: breath): from Latin spīrāculum vent, from spīrāre to breathe]
spi•ra•cle(ˈspaɪ rə kəl, ˈspɪr ə-)
1. a breathing hole; an opening by which a confined space has communication with the outer air; air hole; blowhole.
2. one of the external orifices of the respiratory system in certain invertebrates.
[1300–50; Middle English < Latin spīrāculum air hole =spīrā(re) to breathe + -culum -cle2]
spi•rac′u•lar (-ˈræk yə lər) adj.
An opening through which certain animals breathe, such as the blowhole of a whale or one of the openings in the exoskeleton of an insect.
A hole through which a creature breathes, such as in the abdomen of an insect.
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|Noun||1.||spiracle - a breathing orifice |
orifice, porta, opening - an aperture or hole that opens into a bodily cavity; "the orifice into the aorta from the lower left chamber of the heart"
blowhole - the spiracle of a cetacean located far back on the skull
stigma - an external tracheal aperture in a terrestrial arthropod