A convocation is a meeting or ceremony attended by a large number of people.
例句
...a convocation of the American Youth Congress.美国青年代表大会的会议
英汉词典释义
n.
召集
They regretted agreeing to the convocation of that meeting.他们后悔同意召开这个会议。We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。