三味線しゃみせんの駒こま

Meanings

1

noun

shamisen bridge

The small wooden piece placed on the skin of a shamisen that supports the strings and transmits vibration.

pony, horse, colt

駒こま
General term for a bridge on a stringed instrument; 三味線の駒 specifies the shamisen bridge.
三味線しゃみせん
The three-stringed Japanese instrument itself; 三味線の駒 is a part of it.

Compound of 三味線 (shamisen) and 駒 (bridge). The exact historical derivation is straightforward; the term is a literal description of the part.