A cluster is a small group or bunch of something.
In biology and health sciences:
- In genetics and biotechnology, a cluster may refer to a group of closely gathered genes within a chromosome.
- Cancer cluster, in biomedicine, an occurrence of a greater-than-expected number of cancer cases
- Cluster headache
- Winter cluster, in beekeeping, a well-defined cluster of honey bees in cold temperatures
- Cluster (epidemiology) refers to a grouping of cases of disease, possibly an outbreak
- In genomics, a cluster often refers to a group of genes (or proteins, or metabolites) whose expression or concentration is similar across a range of conditions (see data clustering).
In science fiction:
- A less common name for a bicycle cogset, either a freewheel, or cassette.
- Cluster bomb, air-dropped or ground launched shells
- Cluster diagram, general type of diagram, which represents some kind of cluster.