- a structure projecting from the side or main deck of a vessel to support a gun or the outer edge of a paddle box.
- a buoyant appendage at the gunwale of a canoe to resist capsizing.
- Aeronautics. a protuberance at the side of a flying-boat hull, designed to increase lateral stability in the water.
Origin of sponson
First recorded in 1825–35; variant of expansion
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for sponson
There he lay, along one side of the tank between the engine and the sponson.
McKnutt signalled to him, and he opened fire from his sponson.
A bomb exploded directly beneath the sponson, where the dead body had fallen.
His tun of a torso bulged roundly out in front of me like the sponson of a battleship.Yellowstone Nights
An eager gunner endeavoured to pass one of the tanks, but his gun caught the sponson and slipped off into the mud.A Company of Tanks
W. H. L. Watson
- navy an outboard support for a gun enabling it to fire fore and aft
- a semicircular gun turret on the side of a tank
- a float or flotation chamber along the gunwale of a boat or ship
- a structural projection from the side of a paddle steamer for supporting a paddle wheel
- a structural unit attached to a helicopter fuselage by fixed struts, housing the main landing gear and inflatable flotation bags
C19: perhaps from expansion