air sac

  1. a sac containing air.

  1. any of certain cavities in a bird's body connected with the lungs.

  2. a saclike dilation of the wall of a trachea in many insects.

Origin of air sac

First recorded in 1820–30

Words Nearby air sac Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use air sac in a sentence

British Dictionary definitions for air sac

air sac

  1. any of the membranous air-filled extensions of the lungs of birds, which increase the efficiency of gaseous exchange in the lungs

  2. any of the thin-walled extensions of the tracheae of insects having a similar function

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for air sac

air sac

  1. An air-filled space in the body of a bird that forms a connection between the lungs and bone cavities and aids in breathing and temperature regulation.

  1. A saclike enlargement in the trachea of an insect.

  2. A baglike piece of skin or tissue below the jaw of certain animals, such as the bullfrog and orangutan, that can be inflated to increase sound production.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.