air sac


Definition of air sac

1 : one of the air-filled spaces in the body of a bird connected with the air passages of the lungs
3 : a thin-walled dilation of a trachea occurring in many insects

Examples of air sac in a Sentence

Recent Examples on the Web With an electric zap, the liquid shifts forward; its body follows with the air sac acting like a tail. Rasha Aridi, Smithsonian Magazine, 22 Dec. 2021 The lizards could remain underwater for up to 18 minutes while rebreathing through the air sac. Elizabeth Gamillo, Smithsonian Magazine, 27 May 2021 American Zoologist Horned screamers have air sacs under their skin that reduce the birds’ weight and help them glide long distances through the air. National Geographic, 28 May 2020 As the air sacs are infected and damaged, this triggers the immune system, which can lead to a dangerous condition called a cytokine storm. Mark Johnson, Milwaukee Journal Sentinel, 16 May 2020 When those air sacs become clogged, the lungs stiffen up. oregonlive, 7 Apr. 2020 Ventilators not only help people breathe but also can provide pressure that holds the lungs open so the air sacs don’t collapse. Patricia Callahan, ProPublica, 30 Mar. 2020 The extra-large hyoid bones in their vocal tract house massive air sacs that amplify their bombastic voice to superlative heights; they are often regarded as the loudest of any land animal. Jessica Boddy, Popular Science, 3 Feb. 2020 One is called organizing pneumonia, which is when the tiny airways and air sacs become inflamed. Erika Edwards, NBC News, 5 Dec. 2019 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'air sac.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of air sac

circa 1805, in the meaning defined at sense 1

Learn More About air sac

Time Traveler for air sac

Time Traveler

The first known use of air sac was circa 1805

See more words from the same year

Dictionary Entries Near air sac

air root

air sac

air-sac disease

See More Nearby Entries 

Statistics for air sac

Cite this Entry

“Air sac.” Dictionary, Merriam-Webster, Accessed 29 Jun. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for air sac

air sac


Kids Definition of air sac

: one of the small pouches in the lungs where oxygen and carbon dioxide are exchanged

air sac


Medical Definition of air sac

More from Merriam-Webster on air sac Encyclopedia article about air sac


Test Your Vocabulary

Name That Food

  • a-light
  • Name these cookies!
True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!