air sac

noun

1

: one of the air-filled spaces in the body of a bird connected with the air passages of the lungs

2

: alveolus sense 1b

3

: a thin-walled dilation of a trachea occurring in many insects

Examples of air sac in a Sentence

Recent Examples on the Web

Bronchitis can lead to pneumonia, a deeper and far more serious infection of the lungs’ air sacs. —Landon Mion, Fox News, 19 Feb. 2025

Created in 1969 by Stanford engineers Victor Scheinman and Larry Leifer, the arm could extend by inflating several of 28 air sacs sandwiched between seven metal disks. —IEEE Spectrum, 27 Apr. 2011

Damage to the alveoli (the tiny air sacs in the lungs that exchange carbon dioxide and oxygen) The most common cause of COPD is tobacco smoking. —Soma Mandal, Verywell Health, 4 Feb. 2025

The researchers observed that patients and mice with breast cancer had high concentrations of aspartate in their interstitial fluid, the fluid that fills the spaces between the air sacs and surrounding blood vessels in the lungs. —New Atlas, 1 Jan. 2025

Word History

First Known Use

circa 1805, in the meaning defined at sense 1

Rhymes for air sac

• aback
• anzac
• attack
• backpack
• backtrack
• bareback
• blackjack
• brownback
• buyback
• callback
• cognac
• comeback

Kids Definition

air sac

noun

1

: one of the air-filled spaces connected with the lungs of a bird

2

: one of the thin-walled microscopic pouches in which gases are exchanged in the lungs

Medical Definition

air sac

noun

: alveolus sense b