-sounding-boar-

n. 1. (Mus.) A thin board which propagates the sound in a piano, in a violin, and in some other musical instruments. [ 1913 Webster ]

2. A board or structure placed behind or over a pulpit or rostrum to give distinctness to a speaker's voice. [ 1913 Webster ]

3. pl. See Sound boarding, under Sound, a noise. [ 1913 Webster ]