Definition of "spiracle" []

• Zoology A respiratory aperture, especially: (noun)
• Zoology Any of several tracheal openings in the exoskeleton of an insect or a spider. (noun)
• Zoology A small respiratory opening behind the eye of certain fishes, such as sharks, rays, and skates. (noun)
• Zoology The blowhole of a cetacean. (noun)
• An aperture or opening through which air is admitted and expelled. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "A very large dome, built with great care in the centre or pole, contains another small vault as it were rising out of it, and in this is a spiracle, which is right over the altar."
• "At the end, which I was not long in reaching, a breath of wind suggested that what Gunnie had called a spiracle stretched from the roof to this place."
• "A very large dome, built with great care in the cen - tre or pole, contains another small vault as it were rising out of it, and in this is a spiracle, which is right over the altar."