General English

General Science

  • noun a group of similar things that are close together
  • noun a number of similar events happening at a similar time or in a similar place


  • noun the four cup attachments of a milking machine, attached to the teats of the cow’s udder


  • A region of space with a high density of stars or galaxies. Clusters of galaxies are often grouped in superclusters which are the largest organised objects known. Types of star cluster include open and the more tight-packed globular clusters. Open or galactic clusters – like the Pleiades in Taurus, which are visible to the naked eye – contain a few hundred stars in a space of a few hundred cubic parsecs. Globular clusters can include up to a million stars in a somewhat larger volume.
  • (written as Cluster)
    European Space Agency mission destroyed on 4 June 1996, upon launching with the Ariane V rocket. Cluster consisted of four satellites which would have been placed 100km apart to make measurements in three dimensions of the Earth’s magnetosphere and its interactions with the incoming particles of the solar wind.


  • noun one or more sectors on a hard disk that are used to store a file or part of a file
  • noun a number of terminals, stations, devices, or memory locations, grouped together in one place and controlled by a cluster controller


  • A fixed number of disk sectors treated as a unit. It is the smallest unit of storage that a computer operating system can handle. Also called allocation unit.
  • Two or more hardware devices or systems working as a unit.

Health Economics

  • (written as Cluster)
    Groupings of events that are thought not to be the product of mere chance.

Information & Library Science

  • noun a small group of similar things


  • noun a group of things or people taken together


  • noun a group of small items which cling together
  • noun a significant subset in a statistical sample, e.g. of numbers of people affected by a particular disease or condition