air cushion

WordReference Random House Unabridged Dictionary of American English © 2025

air′ cush′ion, 

1. an inflatable, airtight cushion.
2. Hydraulics See air chamber (def. 2).
3. an air bag.
• 1830–40
air′-cush′ioned, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

air cushion noun

1. an inflatable cushion, usually made of rubber or plastic
2. the pocket of air that supports a hovercraft