Plucked musical instrument, usually with a triangular body and three strings, used chiefly for Russian folk music (9)

(Other definitions for balalaika that I've seen before include "Stringed instrument used for Russian folk music" , "Three-stringed, triangularbodied Russian instrument" , "Three-stringed instrument used to play Russian folk music" , "Instrument with three strings and a triangular body" , "Russian guitar-like instrument" .)