spiracle

American  

[spahy-ruh-kuhl, spir-uh-] / ˈspaɪ rə kəl, ˈspɪr ə- /

noun

1. a breathing hole; an opening by which a confined space has communication with the outer air; air hole.

2. Zoology.

   1. an aperture or orifice through which air or water passes in the act of respiration, as the blowhole of a cetacean.

   2. an opening in the head of sharks and rays through which water is drawn and passed over gills.

   3. one of the external orifices of the tracheal respiratory system of certain invertebrates, usually on the sides of the body.

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spiracle British  

/ ˈspaɪərəkəl, spɪˈrækjʊlə, ˈspaɪrə- /

noun

1. any of several paired apertures in the cuticle of an insect, by which air enters and leaves the trachea

2. a small paired rudimentary gill slit just behind the head in skates, rays, and related fishes

3. any similar respiratory aperture, such as the blowhole in whales

4. geology a protrusion of sediment into a lava flow, formed by the explosive transition of water into steam

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spiracle Scientific  

/ spĭr′ə-kəl,spī′rə- /

1. 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.

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Other Word Forms

• prespiracular adjective
• spiracular adjective
• spiraculate adjective

Etymology

Origin of spiracle

1300–50; Middle English < Latin spīrāculum air hole, equivalent to spīrā ( re ) to breathe + -culum -cle ²

Example Sentences

The book lung looks like a book with many pages and is located just anterior to a spiracle in the ventral abdomen.

From Textbooks • Jan. 1, 2015

The canal leading from the spiracle to the inside of the head soon developed another use.

From Slate • Jan. 27, 2014

Transmitting vibrations through the air to the brain would become the next major use of the spiracle canal.

From Slate • Jan. 27, 2014

Breathing through the spiracle gives the fish a big evolutionary advantage as they can surface to breathe while keeping their eyes underwater, wary for predators.

From Slate • Jan. 27, 2014

Magnified. b, spiracle on prothorax; c, protruded head region; d, tail-end with functional spiracles; e, f, head region with mouth hooks protruded; g, hooks retracted; h, eggs.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" by Various