a group of similar things that are close together, sometimes surrounding something

Have a look at the cluster of galaxies in this photograph. 看看这张照片上的星系群。

There was a cluster of fans around him, asking for autographs. 一大群崇拜者围着他，找他签名。

a group of two or more consonant sounds that are pronounced together with no vowel sound between them

The /str/ at the beginning of "stray" is a cluster. “stray”这个单词的前三个字母str组成了一个辅音丛。

The word "glimpsed" ends with the consonant cluster /mpst/.