A cluster of people or things is a small group of them close together.
例句
...clusters of men in formal clothes...一群群身著正裝的男人There's no town here, just a cluster of shops, cabins and motels at the side of the highway.這兒沒有城鎮，只在公路邊上有一片商店、小木屋和汽車旅館。
VERB
(人)聚集
If people cluster together, they gather together in a small group.
例句
The passengers clustered together in small groups...乘客們三五成群聚在一起。The children clustered around me.孩子們聚集在我的周圍。