noun
plectrum sound; sound of a pick
Refers specifically to the sound produced when a plectrum (撥/ばち) strikes the strings of a shamisen, biwa, or similar instrument. A music-domain term.
三味線の撥音が心地よく響いた。
The sound of the shamisen plectrum resonated pleasantly.
撥 is the plectrum itself; 撥音 is the sound it makes.
Compound of 撥 (ばち, 'plectrum') + 音 (おと, 'sound').