noun
vice-chairman; deputy speaker
Used for the vice-chairperson of a legislative body, committee, or similar assembly. Often paired with 議長 (chairman/speaker).
彼は市議会の副議長に選ばれた。
He was elected vice-chairman of the city council.
議長が不在のときは副議長が議事を進行する。
When the chairman is absent, the vice-chairman presides over the proceedings.
副委員長 is vice-chairman of a committee, while 副議長 is specifically for a deliberative assembly or council.
Compound of 副 (vice-, deputy) and 議長 (chairman, speaker).