contractile vacuole
- a membrane-enveloped cellular organelle, found in many microorganisms, that periodically expands, filling with water, and then contracts, expelling its contents to the cell exterior: thought to be important in maintaining hydrostatic equilibrium.
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Origin of contractile vacuole
First recorded in 1875–80
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018