cluster
Pluralclusters
Verbclusters, clustering, clustered
Pluralclusters
Formsclusters, clustering, clustered
- 1A bunch or group of several discrete items located close to one another.
A cluster of red berries weighed down the branch.
Tiny clusters of crystals formed along the cave wall.
Similarbunch, group, clump, mass, knot
Note
The root sense is an old one. Old English cluster or clyster meant a bunch or a branch, from a Germanic root meaning 'to clump'. Grapes are the early image: Spenser in 1595 writes of 'great glusters of ripe grapes', and the King James Bible of 1611 laments that there is 'no cluster to eat'. Modern use names the members with of: a cluster of islands, of flowers, of berries.
- 2A number of people or animals collected in one place or grouped together; a crowd, mob, or swarm.
A cluster of reporters waited outside the courthouse for the verdict.
Penguins huddled in tight clusters against the wind.
Similargroup, huddle, knot, crowd, bunch
Note
The living crowd, long pictured as bees. Samuel Purchas (1625) has people waiting 'as bees do in the sun, all in a cluster'. Milton's Paradise Lost (1667) sends bees out 'in clusters'. In Shakespeare's Coriolanus the word is a sneer at the mob that hooted a man out of the city. Modern use is neutral, applied to reporters and swarming moths alike.
- 3To gather or assemble into a close group; to come together in one place.
Fans cluster outside the stadium hours before each game.
Air bubbles clustered along the edge of the glass.
Similargather, congregate, assemble, crowd, huddle
Note
The everyday verb, usually followed by a preposition of place: children clustered around a puppy, or Wordsworth's curls that 'cluster'd round her head'. It reaches past the physical as well. Edward Young's 'Woes cluster; rare are solitary woes' (1742) makes misfortunes gather like a crowd. Henry Lyte's Dodoens translation (1578) already has fruit that 'clustereth together'.
- 4To collect animals, people, objects, or data points into close groups.
The florist clustered the white roses at the center of the arrangement.
Researchers cluster the samples by genetic similarity before analysis.
Similargroup, bunch, gather, collect
Oppositescatter, disperse, spread
Note
Mostly met in the passive, as in Richard Steele's jewels 'clustered in her bosom' (1712), or with data points clustered by similarity. Earlier writers also used it reflexively. In Fredrika Bremer's The Home (1843), little heads 'clustered themselves about her'. Modern English would drop the reflexive pronoun and use the intransitive verb: the heads clustered about her.
- 5A group of computers that work together, sharing tasks as a coordinated system.
The lab runs its weather simulations on a cluster of two hundred servers.
Cloud providers maintain enormous clusters in data centers around the world.
Note
In computing the members are machines joined by a network and set to work on a shared problem. Fayez Gebali's Algorithms and Parallel Computing (2011) notes that a local area network typically ties them together. The fuller term computer cluster is used wherever context might leave the bare word unclear. Two computers are already enough to make one.
- 6A group of cases of the same disease occurring close together in place or time.
Investigators traced the cluster of food poisoning cases to a single restaurant.
The county reported several clusters of measles in communities with low vaccination rates.
Similaroutbreak
Note
Epidemiologists name the disease in front, as in a leukemia cluster. The members are cases, and closeness can be in time as well as in place: cases bunched into a few weeks count just as cases bunched into one town do. Whether such a grouping is real or merely chance is the question the statistical sense is built to answer.
- 7A group of stars or galaxies that lie close together in space and are held together by their mutual gravity.
Astronomers photographed a dense cluster of young stars inside the nebula.
The Virgo cluster contains well over a thousand galaxies.
Note
Astronomers usually put a proper name in front: the Pleiades cluster, or the invented Hawking Eta cluster of BioWare's Mass Effect (2007). The compounds star cluster and galaxy cluster say which scale is meant. The difference is large: a few stars and a crowd of galaxies share the bare word. The grouping is defined by how close the objects look in the sky.
- 8To cover with clusters, or to scatter or distribute objects within an area so that they form clusters.
By late spring the hillside was clustered with wildflowers in patches of yellow and purple.
Decorators cluster tiny lights along the ceiling beams for the holidays.
Similardot, stud, sprinkle, group, bunch
Note
Here the verb paints a finished scene rather than an action. It lives mostly in the passive, with 'with' naming what is scattered: the sea is clustered with islands. The subject is the place that receives the clusters. That separates it from the gathering-into-groups verb, where the things themselves are what get clustered.
- 9Euphemistic form of clusterfuck.
The product launch was a complete cluster, with broken links and a crashing site.
Between the canceled flights and the lost luggage, the whole trip became a cluster.
Note
A polite clipping. Dropping the vulgar second half of clusterfuck leaves a word that is usable where the full form is not, though listeners still hear the whole. Only the chaos meaning carries over. The compound's other vulgar uses, for an orgy or for making a mess of something, do not. It remains slang, so keep it for casual talk.
- 10In statistics, a subset of a population whose members are similar to one another and distinct from others enough to form a separate group; also, a statistically significant grouping in observed data.
The analysis revealed a tight cluster of voters who gave nearly identical answers.
Epidemiologists checked whether the cases formed a genuine cluster or just random scatter.
Note
Statistics asks two things of a cluster. Its members must resemble one another, and they must stand apart from the rest. In the stricter use, a clump that could have arisen by chance does not yet qualify, because the grouping must be statistically significant. The method that finds clusters is cluster analysis, and the procedure itself is the verb to cluster.
- 11A pronounceable group of consonants occurring together in a word, without a vowel between them.
English permits a cluster of three sounds at the beginning of words like 'splash'.
Japanese speakers often break up borrowed clusters by inserting vowels between the consonants.
Note
The key word is pronounceable: the consonants must be ones a speaker can say together, as in the three that open scrub. Sounds are counted, not letters. Consonant cluster is the full term and the safer choice outside phonetics, where the bare word could be read in another sense. The lexical-bundle sense is the linguist's other cluster.
- 12A logical unit of data storage on a disk, made up of one or more physical sectors.
Formatting the drive with a smaller cluster size left far less wasted space.
The recovery tool scanned every cluster for fragments of the deleted file.
Note
A file-system term that sits between the hardware and the files. The disk is divided physically into sectors, and the system groups one or more of them into a cluster as its working unit of storage. The word overlaps closely with block, which names much the same idea. Cluster size is the setting that decides how many sectors make up one unit.
- 13A batch of bombs or mines let loose at the same time, their explosions combining into a single blast.
The bomber released a cluster over the rail yard, and the explosions came almost as one.
Engineers detonated the remaining clusters in place rather than risk moving them.
- 14An ensemble of bound atoms or molecules, especially of a metal, intermediate in size between a single molecule and a bulk solid.
A cluster of fifty-five silver atoms shows properties that neither a lone atom nor the bulk metal displays.
Researchers deposited the clusters onto a titanium dioxide surface to test their catalytic activity.
Note
Physical chemistry uses the word for matter caught between two familiar scales. A cluster is too large to count as a molecule and too small to behave like a bulk solid. Metals are the typical case, so the element is often named: a cluster of silver atoms, a metal cluster. Unlike the everyday sense, the members are bound to one another, not merely near.
- 15A chord of three or more notes built from seconds, so that adjacent notes sound together.
The movement ends on a soft cluster held in the piano's lowest register.
She struck the clusters with her palm, sounding every key under her hand at once.
Note
In music the word describes how a chord is built. Its notes are stacked in seconds, the smallest steps of the scale, rather than in the thirds of ordinary harmony. Three neighboring notes are enough to make one. Because the pitches sit so close, the result tends to be heard as a dense band of sound more than as separate notes.
- 16A small bronze or silver device shaped like a twig of oak leaves and acorns, worn on a ribbon to show the wearer has received the same award or decoration before.
She wore a silver cluster on the ribbon, marking repeated awards of the same commendation.
His Bronze Star came with a cluster after the second deployment.
Note
A clipped name used in US military awards. In full the device is an oak leaf cluster, and oakleaf is another short name for it. It marks repetition rather than a new honor, so it is spoken of as an addition to the decoration: a Bronze Star with a cluster. Readers outside that setting may need the full term to recognize the device.
- 17A sequence of two or more words that occurs with high frequency in a language but is not idiomatic; a lexical bundle.
The corpus software listed every four-word cluster that occurred at least ten times per million words.
Recurrent clusters like 'in terms of' appear in academic writing across many disciplines.
Note
Here frequency, not meaning, makes the group. In accordance with, so far and the results of all qualify, though the last is not even a complete phrase. That is what separates a cluster from an idiom: its sense is simply the sum of its words. Lexical bundle is the more explicit term, and bundle and chunk are used too. Do not confuse it with the consonant cluster of phonetics.
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Practice
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Origin
The noun comes from Middle English cluster (a bunch, spray, or compact mass), from Old English cluster or clyster (cluster, bunch, branch), from Proto-Germanic roots meaning "to clump or lump together," possibly going back to a Proto-Indo-European root meaning "to ball up" or "to amass." It is probably a doublet of clot, and the verb is derived from the noun.