Meaning of waterbed

wa•ter•bed

Pronunciation: (wô'tur-bed", wot'ur-), [key]
— n.
  1. a bed having a liquid-filled rubber or plastic mattress in a rigid, often heated, waterproof frame, and providing a surface that conforms to the sleeper's body in any position.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.