1.a group of similar things that are close together, sometimes surrounding something
Have a look at the cluster of galaxies in this photograph.
There was a cluster of fans around him, asking for autographs.
2.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.
The word "glimpsed" ends with the consonant cluster /mpst/.
3.(of a group of similar things or people) to form a group, sometimes by surrounding something or someone, or to make something do this
People clustered around the noticeboard to read the exam results.
The hens cluster together at the sight of strangers, going quiet.
4.to form or gather together
All his grandchildren clustered around him.
5.a group of similar things growing or held together, or a group of people or things that are close together
dense clusters of delicate pink blossoms
This section of town has a large cluster of fast-food restaurants.
6.a group of similar things that are close together in a small area
There is a cluster of hi-tech businesses in the city's industrial park.
7.a group of similar events that happen within a small area or among a small group of people
The study will look at an apparent cancer cluster among workers at the factory.
8.a group of computers connected together to work as one larger computer and to improve their performance
9.to happen a lot in the same small area or in the same way
Most young firms tend to cluster in the finance, IT, telecoms, and retail industries.
10.to stand or be positioned close together in a group
People clustered around the noticeboard to read the announcement.