Definition of: spiracle

(spir′ə·kəl, spī′rə-) noun
1. Zool. a An aperture or orifice for the passage of air or water in the respiration of terrestrial arthropods, as the grasshopper and locust. b A breathing hole, as the blowhole or nostril of a cetacean.
2. A minute cone formed on a stream of lava by escaping gases.
3. Any opening to admit or expel air; an airhole. [<OF <L spiraculum airhole <spirare breathe]