The word cluster often refers to a group of things of the same kind that are held together—a bundle. Sometimes, it specifically refers to a group of things that grow together, like a cluster of grapes. A synonym for this sense is bunch.

More generally, the word cluster can refer to any collection of things positioned closely together. These things can be tangible, as in There is a cluster of people around the gate, or intangible, as in data cluster or Epidemiologists are tracking multiple outbreak clusters. 

A very general synonym is group (or, perhaps more precisely, grouping). The word clutch can also refer to a group or bunch of things.

Cluster can also be used as a verb meaning to form into such a group. Synonyms are assemble, gather, and the verb sense of group.

What is another name for a cluster of flowers?

A cluster of flowers is more commonly known as a bunch of flowers or simply a bouquet. The word clutch could also be used.

Cluster refers to close groups. It can refer to both tangible and intangible things.

Here are some examples of cluster in a sentence:

• It’s right over there, near that cluster of bushes.
• I think we’ll find our answer by analyzing these data clusters. 
• The people clustered around the stage to hear the speech.