What is the meaning of 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, etc.

To place (a patient) on a spine board.

The port or larboard side of a ship

Source: wiktionary.org