1660s, spinette, "small harpsichord," from Middle French espinette (16c., Modern French épinette), from Italian spinetta, said by Scaliger to be a diminutive of spina "thorn, spine," from Latin spina "thorn" (see spine), so called because the strings were plucked with thorn-like quills [Barnhart]. The other theory (favored by Klein and assigned "greater probability" by OED) dates to early 17c. and claims the word is from the name of the Venetian inventor, Giovanni Spinetti (fl. c. 1503). As "small, upright piano" from 1936.