may refer to:

Science and technology

Astronomy

Cluster (spacecraft) Ariane flight V88 was the failed maiden flight of the Arianespace Ariane 5 rocket, vehicle no. 501, on 4 June 1996. It carried the Cluster spacecraft, a constellation of four European Space Agency research satellites. The launch ended in fai ...

, constellation of four European Space Agency spacecraft * Cluster II (spacecraft), a European Space Agency mission to study the magnetosphere * Asteroid cluster, a small asteroid family *

Galaxy cluster A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. Clusters consist of galax ...

, large gravitationally bound groups of galaxies, or groups of groups of galaxies *

Supercluster A supercluster is a large group of smaller galaxy clusters or galaxy groups; they are among the largest known structures in the universe. The Milky Way is part of the Local Group galaxy group (which contains more than 54 galaxies), which in tu ...

, the largest gravitationally bound objects in the universe, composed of many galaxy clusters *

Star cluster A star cluster is a group of stars held together by self-gravitation. Two main types of star clusters can be distinguished: globular clusters, tight groups of ten thousand to millions of old stars which are gravitationally bound; and open cluster ...

Globular cluster A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...

, a spherical collection of stars whose orbit is either partially or completely in the halo of the parent galaxy **

Open cluster An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

, a spherical collection of stars that orbits a galaxy in the galactic plane

Biology and medicine

* Cancer cluster, in biomedicine, an occurrence of a greater-than-expected number of cancer cases *

Cluster headache Cluster headache is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye, eye(s). There is often accompanying eye watering, nasal congestion, or swelling around the eye on the aff ...

, a neurological disease that involves an immense degree of pain *

Cluster of differentiation The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophe ...

, protocol used for the identification and investigation of cell surface molecules present on white blood cells *

Winter cluster In beekeeping, a winter cluster is a well-defined cluster of honey bees that forms inside a beehive when the air temperature dips below . Honey bees are one of only a few kinds of insects that survive the winter as a colony. As the outside air t ...

, in beekeeping, a well-defined cluster of honey bees in cold temperatures * Disease cluster, a grouping of cases of disease *

Gene cluster A gene cluster is a group of two or more genes found within an organism's DNA that encode similar peptide, polypeptides or proteins which collectively share a generalized function and are often located within a few thousand base pairs of each othe ...

, a group of genes (or proteins, or metabolites) whose expression or concentration is similar across a range of conditions * Cluster of microorganisms, as in a

colony A colony is a territory subject to a form of foreign rule, which rules the territory and its indigenous peoples separated from the foreign rulers, the colonizer, and their ''metropole'' (or "mother country"). This separated rule was often orga ...

Chemistry

Cluster chemistry Nanoclusters are atomically precise, crystalline materials most often existing on the 0-2 nanometer scale. They are often considered kinetically stable intermediates that form during the synthesis of comparatively larger materials such as semic ...

, an array of bound atoms intermediate in character between a molecule and a solid

Computer science

Computer cluster A computer cluster is a set of computers that work together so that they can be viewed as a single system. Unlike grid computers, computer clusters have each node set to perform the same task, controlled and scheduled by software. The newes ...

, a set of computers that work together *

Data cluster In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. For most disks, each sector stores a fixed amount of user-accessible data, traditionally 512 bytes for hard disk drives (HDDs), and 2048 byte ...

, a group of disk sectors used in a File Allocation Table

Economics

Business cluster A business cluster is a geographic concentration of interconnected businesses, suppliers, and associated institutions in a particular field. Clusters are considered to increase the productivity with which companies can compete, nationally and gl ...

, a geographic cluster of competitive businesses * Cluster theory, a theory that states concentrating industries in specific regions creates several advantages

Education

* CLUSTER, the Consortium Linking Universities of Science and Technology for Education and Research (a collection of twelve European universities which focus on science and engineering)

Equipment

Cluster bomb A cluster munition is a form of air-dropped or ground-launched explosive weapon that releases or ejects smaller submunitions. Commonly, this is a cluster bomb that ejects explosive bomblets that are designed to kill personnel and destroy vehi ...

, a type of air-dropped or ground-launched shells * Instrument cluster of an automobile * A bicycle

cogset On a bicycle, the cassette or cluster is the set of multiple sprockets that attaches to the hub on the rear wheel. A cogset works with a rear derailleur to provide multiple gear ratios to the rider. Cassettes come in two varieties, freewheels or ...

, either a freewheel, or cassette * The set of tubes attached to a cow's teats for

automatic milking Automatic milking is the milking of dairy animals, especially of dairy cattle, without human labour. Automatic milking systems (AMS), also called voluntary milking systems (VMS), were developed in the late 20th century. They have been commerciall ...

Linguistics

Consonant cluster In linguistics, a consonant cluster, consonant sequence or consonant compound is a group of consonants which have no intervening vowel. In English, for example, the groups and are consonant clusters in the word ''splits''. In the education fie ...

, a group of

consonants In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract, except for the h sound, which is pronounced without any stricture in the vocal tract. Examples are and pronou ...

which have no intervening

vowel A vowel is a speech sound pronounced without any stricture in the vocal tract, forming the nucleus of a syllable. Vowels are one of the two principal classes of speech sounds, the other being the consonant. Vowels vary in quality, in loudness a ...

Language cluster A dialect is a variety of language spoken by a particular group of people. This may include dominant and standardized varieties as well as vernacular, unwritten, or non-standardized varieties, such as those used in developing countries or iso ...

or dialect cluster, a geographic distribution of languages

Math and statistics

Cluster analysis Cluster analysis or clustering is the data analyzing technique in which task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more Similarity measure, similar (in some specific sense defined by the ...

, a set of techniques for grouping a set of objects based on intrinsic similarities *

Cluster sampling In statistics, cluster sampling is a sampling plan used when mutually homogeneous yet internally heterogeneous groupings are evident in a statistical population. It is often used in marketing research. In this sampling plan, the total populat ...

, a sampling technique used when "natural" groupings are evident in a statistical population *

Cluster graph In graph theory, a branch of mathematics, a cluster graph is a graph formed from the disjoint union of complete graphs. Equivalently, a graph is a cluster graph if and only if it has no three-vertex induced path; for this reason, the cluster g ...

, in graph theory, a disjoint union of complete graphs * Clusterable graph, in

balance theory In the psychology of motivation, balance theory is a theory of attitude change, proposed by Fritz Heider. It conceptualizes the cognitive consistency motive as a drive toward psychological balance. The consistency motive is the urge to maintain one ...

* Cluster algebra, a class of commutative rings used in representation theory *

Cluster expansion In statistical mechanics, the cluster expansion (also called the high temperature expansion or hopping expansion) is a power series expansion of the partition function of a statistical field theory around a model that is a union of non-interact ...

, a technique in statistical mechanics and quantum field theory

Physics

* Cluster (physics), a small group of atoms or molecules

Urban development

* Cluster home, a type of housing development * Research-intensive cluster, a region with a high density of research-oriented organizations *

Urban agglomeration An urban area is a human settlement with a high population density and an infrastructure of built environment. Urban areas originate through urbanization, and researchers categorize them as cities, towns, conurbations or suburbs. In urbani ...

, a cluster concept in urban development (a

human settlement In geography, statistics and archaeology, a settlement, locality or populated place is a community of people living in a particular location, place. The complexity of a settlement can range from a minuscule number of Dwelling, dwellings gro ...

with a high

population density Population density (in agriculture: Standing stock (disambiguation), standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geog ...

and an

infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and pri ...

built environment The term built environment refers to human-made conditions and is often used in architecture, landscape architecture, urban planning, public health, sociology, and anthropology, among others. These curated spaces provide the setting for human ac ...

)

Philosophy and religion

* Khandha, a Buddhist concept of five material and mental factors that take part in the rise of craving and clinging * Proper name (philosophy), a cluster of propositions that in combination pick out a unique referent

Arts and media

Music

* Tone cluster, a musical chord comprising at least three consecutive tones in a scale * ''Cluster'' (album), the 1971 eponymous album by the band Cluster *

Cluster (band) Cluster was a German musical duo consisting of Hans-Joachim Roedelius and Dieter Moebius, formed in 1971 and associated with West Germany's krautrock and kosmische music scenes.Bush, John. Allmusic: Cluster Retrieved 24 February 2005. Origin ...

, a German electronic group * "Cluster", a track from the album '' Ben Bu Sarkiyi Sana Yazdim'' by Cem Adrian * "Cluster", a song by P-Model from the album '' Big Body'' * Cluster One, the first track on Pink Floyd's 1994 album ''The Division Bell'' * "Cluster", an extended play by the pop-punk band Waterparks

Other media

* ''Cluster'' (novels) by Piers Anthony * ''Cluster'', a poetry collection by Souvankham Thammavongsa * The Cluster, a character from the TV series ''Steven Universe''

Other uses

* Cluster, Pleasants County, West Virginia * Cluster diagram, general type of diagram, which represents some kind of cluster * Clusterfuck or cluster, slang term for a messy situation, arising in the US Marine Corps * Clusters School of Digital Arts, an animation and visual effects training school