- Also called: swim bladder
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 any air-filled sac, such as one of the bladders of seaweeds
WordReference Random House Unabridged Dictionary of American English © 2025
air′ blad′der,
- a vesicle or sac containing air.
- FishAlso called gas bladder, swim bladder. [Ichthyol.]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.
- 1725–35
Collins Concise English Dictionary © HarperCollins Publishers::
'air bladder' also found in these entries (note: many are not synonyms or translations):
Weberian apparatus
- bony fish
- float
- gas bladder
- lungfish
- midshipman
- physoclistous
- physostomous
- pneumatic duct
- sciaenoid
- singingfish
- sound
- sphygmomanometer
- swim bladder