a Japanese musical instrument of the zither family, with a rectangular body and seven to thirteen waxed silk strings
Origin:
Jpn, a generic term for zitherlike stringed instruments
See koto in American Heritage Dictionary 4
nounpl.ko·tos
A Japanese musical instrument similar to a zither, having usually 13, but sometimes as few as 1 or as many as 17, silk strings stretched over an oblong box.