air sac

noun

a sac containing air.
alveolus(def 2).
any of certain cavities in a bird's body connected with the lungs.
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

air raid, air rifle, air right, air root, air route, air sac, air scoop, air scout, air service, air shaft, air shot

Example sentences from the Web for air sac

British Dictionary definitions for air sac

air sac

noun

any of the membranous air-filled extensions of the lungs of birds, which increase the efficiency of gaseous exchange in the lungs
any of the thin-walled extensions of the tracheae of insects having a similar function

Medical definitions for air sac

air sac

n.

A tiny, thin-walled, capillary-rich sac in the lungs where the exchange of oxygen and carbon dioxide takes place. alveolar sac

Scientific definitions for air sac

air sac

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.
See alveolus.
A saclike enlargement in the trachea of an insect.
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.