seatback

plural seatbacks · alternative seat back

1. The usually vertical portion of a chair or similar piece of furniture that supports the back.

   The collection, called Kinesis, features a chair with a sensuous seatback and arms; the sleek lines look as if they would be at home in a Porsche.

   2009 January 1, Stephen Milioti, “The Hand Points the Way”, in New York Times

   1 more example

   The Institute adds that seatback width can be reduced considerably to improve visibility without sacrificing support strength and antiwhiplash protection.

   1968 December, Popular Mechanics, volume 130, number 6, page 20

2. A loose ornamental covering for the back of a sofa or chair.