• WordNet 3.6
    • n spiracle a breathing orifice
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Webster's Revised Unabridged Dictionary
    • Spiracle (Zoöl) A tubular orifice communicating with the gill cavity of certain ganoid and all elasmobranch fishes. It is the modified first gill cleft.
    • Spiracle Any small aperture or vent for air or other fluid.
    • Spiracle (Zoöl) One of the external openings communicating with the air tubes or tracheæ of insects, myriapods, and arachnids. They are variable in number, and are usually situated on the sides of the thorax and abdomen, a pair to a segment. These openings are usually elliptical, and capable of being closed. See Illust. under Coleoptera.
    • Spiracle (Anat) The nostril, or one of the nostrils, of whales, porpoises, and allied animals.
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Century Dictionary and Cyclopedia
    • n spiracle An aperture or orifice.
    • n spiracle In zoology, an aperture, orifice, or vent through which air, vapor, or water passes in the act of respiration; a breathing-hole; a spiraculum: applied to many different formations. Specifically— In Mammalia, the nostril or blow-hole of a cetacean, as the whale, porpoise, etc., through which air, mixed with spray or water, is expelled.
    • n spiracle A vent for small explosive outbreaks, produced upon the surface of a still highly heated and at least partially molten lava-stream by the escape of imprisoned vapors. A little cone of ejected clots may gather around it.
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Chambers's Twentieth Century Dictionary
    • n Spiracle spir′a-kl a breathing-hole: any minute passage
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Webster's Revised Unabridged Dictionary
L. spiraculum, fr. spirare, to breathe: cf. F. spiracule,. See Spirit
Chambers's Twentieth Century Dictionary
L. spiraculum, formed as a double dim. from spirāre, to breathe.


In literature:

But a whale can no more force water through its spiracle or blow-hole than you or I through our nostrils.
"The Cruise of the Cachalot" by Frank T. Bullen
No, he breathes through his spiracle alone; and this is on the top of his head.
"Moby Dick; or The Whale" by Herman Melville
Spiracles behind the eyes.
"Journals Of Expeditions Of Discovery Into Central Australia And Overland" by Edward John Eyre
Larvae, entirely black, with showy eye-like spiracles, polished black head; other larvae having the head brown and black.
"Scientific American Supplement, No. 344, August 5, 1882" by Various
Doubtless the skin pores of these men have taken on the character of spiracles.
"Police!!!" by Robert W. Chambers
There are spiracles on the sides of the thorax, too, but they do not show so plainly as those on the abdomen.
"The Insect Folk" by Margaret Warner Morley
This suggests that the spiracle is really a somewhat modified gill slit.
"Text Book of Biology, Part 1: Vertebrata" by H. G. Wells
Tympanic spiracle: in Diptera, the thoracic spiracle at base of wing.
"Explanation of Terms Used in Entomology" by John. B. Smith
The tip of the tail is projected above the water and air is taken in at two small breathing pores or spiracles.
"An Elementary Study of Insects" by Leonard Haseman
There is a pair of spiracles on each thoracic ring.
"Our Common Insects" by Alpheus Spring Packard