cluster noun
ADJ. little, small | compact, dense
PREP. in a/the ~ The church stood in a small cluster of farmers' cottages. | ~ of a dense cluster of buildings
cluster verb
ADV. closely, tightly | together The group clustered together closely.
PREP. about/around/round The children clustered around their teacher.
You can also check other dicts: cluster (English, 中文解释 ), wordnet sense, Collins Definition