Cluster (noun)

1. A group of similar things that are close together.
2. A number of similar things growing or occurring together.

Origin:

Late 16th century: from french cluster, from a diminutive of clous "nail", used in the sense "something fastened together".

Examples:

1. A cluster of stars can form a galaxy.
2. She picked a cluster of grapes from the vine.
3. The neighborhood was a cluster of small houses.
4. There was a cluster of people waiting for the bus.
5. The scientist studied a cluster of neurons in the brain.