waterbed
/ˈwɔtərˌbɛd/
noun
- A bed with a mattress made of a flexible plastic or vinyl bag filled with water, used for sleeping.
- Waterbeds were very popular in the 1970s and 1980s.
- My grandparents had a waterbed in their guest room, and it felt like floating.
- He bought a heated waterbed to help with his back pain.