bladder(redirected from fallen bladder)
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1. Anatomy a distensible membranous sac, usually containing liquid or gas, esp the urinary bladder
2. a blister, cyst, vesicle, etc., usually filled with fluid
3. a hollow vesicular or saclike part or organ in certain plants, such as the bladderwort or bladderwrack
Any saclike structure in humans and animals, such as a swimbladder or urinary bladder, that contains a gas or functions as a receptacle for fluid.