air bladder Meaning, Definition & Usage

  1. noun an air-filled sac near the spinal column in many fishes that helps maintain buoyancy
    float; swim bladder.

WordNet

Air" blad`der
Definitions
  1. (Anat.) An air sac, sometimes double or variously lobed, in the visceral cavity of many fishes. It originates in the same way as the lungs of air-breathing vertebrates, and in the adult may retain a tubular connection with the pharynx or esophagus.
  2. A sac or bladder full of air in an animal or plant; also an air hole in a casting.

Webster 1913