'Swim bladder' definitions:

Definition of 'swim bladder'

From: WordNet
noun
An air-filled sac near the spinal column in many fishes that helps maintain buoyancy [syn: air bladder, swim bladder, float]

Definition of 'Swim bladder'

From: GCIDE
  • Swim \Swim\, n.
  • 1. The act of swimming; a gliding motion, like that of one swimming. --B. Jonson. [1913 Webster]
  • 2. The sound, or air bladder, of a fish. [1913 Webster]
  • 3. A part of a stream much frequented by fish. [Eng.] [1913 Webster]
  • Swim bladder, an air bladder of a fish.
  • To be in the swim, to be in a favored position; to be associated with others in active affairs. [Colloq.] [1913 Webster]