/ˈklʌs.tɚ/
a group of things of the same type that grow or appear close together （同类物丛生或聚集的）簇，团，束，串
a cluster of stars
星团
The plant bears its flowers in clusters.
这种植物开花成簇。
a leukaemia cluster (= an area where there are more cases of the disease than you would expect)
白血病高发区