backboard

The flat vertical surface to which the basket is attached.

A flat vertical wall with the image of a tennis net drawn or painted on it, designed to practice hitting against such that the ball rebounds.

A spine board.

A board placed at the back of a cart, boat, behind a signal, etc.

• The L.B.S.C.R. favoured backboards for signals wherever these helped visibility. The Great Eastern also made extensive use of backboards.
• He […]had ridden the remainder of the way clinging to the backboard of a cotton wagon.

To place (a patient) on a spine board.transitive

The port or larboard side of a shipuncountableusually

• And to delight in the fact that a hole on the backboard side means that you're safe because you're sitting on the starboard side seems to me to be less than clever.