cluster 英語で:

A cluster is a small group of people or things. When you and your friends huddle awkwardly around the snack table at a party, whispering and trying to muster enough nerve to hit the dance floor, you’ve formed a cluster.

The people seemed clustered in groups of two or three.

large stellar system-of a cluster of Milky Ways

All his grandchildren clustered around him.

cluster of flowers

Have a look at the cluster of galaxies in this photograph.

Only a tiny fracrion of the stars in our galaxy are known to occur in cluster.