a sac containing air.
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.
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
air sac n.
A tiny, thin-walled, capillary-rich sac in the lungs where the exchange of oxygen and carbon dioxide takes place. Also called alveolar 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.
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.
- Air scoop
an air intake that projects into the airflow around a motor vehicle or aircraft in such a way as to provide a steady flow of air for combustion or ventilation. Contemporary Examples Another time, I was shooting a locomotive and it blew up, and some of the stuff got in my air scoop, but I […]
- Air scout
noun a scout belonging to a scout troop that specializes in flying, gliding, etc See Scout Historical Examples Tom had completed his air scout and had refined it to a point where even his critical judgment was satisfied. Tom Swift and his Air Scout Victor Appleton He came a little while after you and Mr. […]
an airplane propeller. Historical Examples The Fokkers late in 1915 had been fitted with guns which fired through the airscrew. The War in the Air; Vol. 1 Walter Raleigh. A good illustration of this may be found in the question of the airscrew. The War in the Air; Vol. 1 Walter Raleigh. The motive power […]
- Air service
the services performed by an airline, as flights between various destinations to transport passengers, freight, and mail. (initial capital letters) (formerly) the air arm of the U.S. military forces. Historical Examples I hope to be transferred to the American air service as soon as possible, returned the smiling Don Hale. Don Hale with the Flying […]