gas bladder

air bladder

noun
  1. a vesicle or sac containing air.
  2. Also called gas bladder, swim bladder. Ichthyology. a gas-filled sac located against the roof of the body cavity of most bony fishes, originally functioning only as a lung, now serving in many higher fishes to regulate hydrostatic pressure.

Origin of air bladder

First recorded in 1725–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for gas-bladder

air bladder

noun
  1. Also called: swim bladder ichthyol an air-filled sac, lying above the alimentary canal in bony fishes, that regulates buoyancy at different depths by a variation in the pressure of the air
  2. any air-filled sac, such as one of the bladders of seaweeds
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

gas-bladder in Science

air bladder

  1. An air-filled sac in many fish that helps maintain buoyancy or, in some species, helps in respiration, sound production, or hearing. Also called swim bladder
  2. See float.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.