Backboard

1. n. A board worn across the back to give erectness to the figure.
2. n. A board which supports the back wen one is sitting;
3. n. A board serving as the back part of anything, as of a wagon.
4. n. A thin stuff used for the backs of framed pictures, mirrors, etc.
5. n. A board attached to the rim of a water wheel to prevent the water from running off the floats or paddies into the interior of the wheel.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.