- A group of similar things that are close together.
- A number of similar things growing or occurring together.
Late 16th century: from french cluster, from a diminutive of clous "nail", used in the sense "something fastened together".
- A cluster of stars can form a galaxy.
- She picked a cluster of grapes from the vine.
- The neighborhood was a cluster of small houses.
- There was a cluster of people waiting for the bus.
- The scientist studied a cluster of neurons in the brain.