noun
acting chairman; acting president
Used in formal meeting contexts for a person temporarily presiding over a meeting or assembly.
議長が遅れているので、副議長が仮議長を務めた。
Since the chairperson was late, the vice-chairperson served as acting chairperson.
副議長 is the vice-chairperson, who may serve as 仮議長 when the chairperson is absent.
Compound of 仮 (かり, 'temporary, provisional') and 議長 (ぎちょう, 'chairperson, president').