wagon seat

noun Furniture.

a plain, unupholstered settee, usually with a slat back, for use either indoors or in a wagon.

Origin of wagon seat

An Americanism dating back to 1850–55
Also called rumble seat.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for wagon seat