促弦

促弦	cù xián	to tighten the strings (of a musical instrument)
促	cù	(bound form) of short duration; hasty; rapid / (bound form) to hasten; to hurry; to urge / (literary) close by; pressed against
弦	xián	bow string / string of musical instrument / watchspring / chord (segment of curve) / hypotenuse / CL:根