Backrest (noun)

A support for the back, typically on a chair or seat.

Origin:

Backrest is formed by back + rest, with back meaning something that supports the back.

Examples:

1. The chair had a comfortable backrest for support.
2. He adjusted the backrest on his office chair to find the most comfortable position.
3. The backrest on the bench was too low for him to sit comfortably.
4. The couch had a built-in backrest for extra comfort.
5. The backrest on the wheelchair was adjustable to provide the right support.