D defs.my
Entry 5 senses Webster, 1913

Backboard

/băk'-bôrdˌ/ · Back·board · IPA /bˈækbˌɔrd/
01 n. A board which supports the back when one is sitting;
  1. 1.
    A board which supports the back when one is sitting;
  2. 2.
    A board serving as the back part of anything, as of a wagon.
  3. 3.
    A thin stuff used for the backs of framed pictures, mirrors, etc.
  4. 4.
    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.
  5. 5.
    A board worn across the back to give erectness to the figure.