backboard

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A board forming or placed at the back of something.
• noun A board used to support an injured person's back, especially during transport.
• noun Basketball The elevated vertical board or surface from which the basket projects.

from The Century Dictionary.

• noun A board for the back; a board placed at the back or serving as the back of something.
• noun A board used in a lathe to sustain the pillars supporting the puppet-bar.
• noun In English [Yorkshire] coal-mining, a thirl or cross-hole communicating with the return air-course.
• In leather manufacturing, to board on the flesh side instead of on the grain side as in regular boarding.

from the GNU version of the Collaborative International Dictionary of English.

• noun A board which supports the back when one is sitting
• noun A board serving as the back part of anything, as of a wagon.
• noun A thin stuff used for the backs of framed pictures, mirrors, etc.
• noun A board attached to the rim of a water wheel to prevent the water from running off the floats or paddles into the interior of the wheel.
• noun A board worn across the back to give erectness to the figure.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun basketball The flat vertical surface to which the basket is attached.
• noun tennis 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 bounces back.
• noun medicine A spine board.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a raised vertical board with basket attached; used to play basketball
• noun a board used to support the back of someone or something