Siminoff, Roger H. (2002). The Luthier's Handbook, p.44. Hal Leonard. ISBN9780634014680. "The soundboard is the most important component of an acoustic instrument. In acoustic terms, it is referred to as a 'plate.'" Or "plaque"".
Gerken, Teja; Simmons, Michael; Ford, Frank; and Johnston, Richard (2005). Acoustic Guitar, p.127. Hal Leonard. ISBN9780634079207. "The soundboard, or top, is the most important component of any guitar, for it is responsible for the majority of the instrument's sound [amplitude]."