When people congregate, they gather together and form a group.
例句
Youngsters love to congregate here in the evenings outside cinemas showing American films...晚上，年輕人喜歡聚集在放映美國電影的電影院外面。Visitors congregated on Sunday afternoons to view public exhibitions.每周日下午，游客成群結隊地來看公開展覽。
英漢詞典釋義
vt. & vi.
(使)集合, 聚集
The crowds congregated in the town square to hear the mayor speak.人群聚集到市鎮廣場上來聽市長講話。
英英詞典釋義
Verb
1. come together, usually for a purpose;
"The crowds congregated in front of the Vatican on Christmas Eve"