The organizer of an event or activity is the person who makes sure that the necessary arrangements are made.
例句
The organisers of the demonstration concede that they hadn't sought permission for it...游行示威的组织者承认他们并未申请批准这次活动。...his campaign organisers who are canvassing for last minute support...为他作最后一刻游说以获取支持的竞选组织者