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

This compensates for the fundamental problem of late-stage emphysema: As tiny air sacs are destroyed, air gets trapped in diseased regions, causing overinflation that leaves sufferers literally stuck holding more and more of their breath. Marie Mccullough,, "Emphysema patients get new option as FDA approves lung valves studied at Temple," 29 June 2018 Birds are also light because much of their insides are filled with air due to extensive space-filling air sacs which are part of their exceptionally efficient respiratory system. Steven Austad,, "Dinosaurs in the garden," 14 Apr. 2018 Daniel, a 12-year-old Bornean orangutan, was dealing with a sinus infection that left him with labored breathing, coughing, frequent mucous production and a distended air sac, the Phoenix Zoo said in a media release. Robert Gundran, azcentral, "Phoenix Zoo orangutan plagued by sinus problems gets groundbreaking surgery," 22 Mar. 2018 Influenza can develop into pneumonia, an infection that causes the lungs' air sacs to become inflamed and fill with fluid. Rachel Ohm, USA TODAY, "Flu widespread in 36 states, CDC reports," 29 Dec. 2017 The kiwi chick sticks its bill into an air sac at the top of the egg, and starts to squeak. Ed Yong, The Atlantic, "How to Raise the Rarest Kiwi," 20 Sep. 2017

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.

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First Known Use of air sac

circa 1805, in the meaning defined at sense 1

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Time Traveler for air sac

The first known use of air sac was circa 1805

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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 

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