# cluster

Pronunciation: US say "KLUS-tur" /ˈklʌstɚ/; UK say "KLUS-tuh" /ˈklʌstə/

## Noun

1. A bunch or group of several discrete items located close to one another.
   - Simple: A group of things that are very close together.
   - _A cluster of red berries weighed down the branch._
   - _Tiny clusters of crystals formed along the cave wall._
2. A number of people or animals collected in one place or grouped together; a crowd, mob, or swarm.
   - Simple: A group of people or animals gathered close together in one place.
   - _A cluster of reporters waited outside the courthouse for the verdict._
   - _Penguins huddled in tight clusters against the wind._
5. A group of computers that work together, sharing tasks as a coordinated system.
   - Simple: A group of computers that are joined together to work as one 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._
6. A group of cases of the same disease occurring close together in place or time.
   - Simple: A group of cases of the same illness that happen near each other or around the same 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._
7. A group of stars or galaxies that lie close together in space and are held together by their mutual gravity.
   - Simple: A group of stars or galaxies that look close together in the night sky.
   - _Astronomers photographed a dense cluster of young stars inside the nebula._
   - _The Virgo cluster contains well over a thousand galaxies._
9. Euphemistic form of clusterfuck. *(slang)* — Euphemistic form of clusterfuck (“a chaotic situation where everything seems to go wrong”).
   - Simple: A milder slang form of clusterfuck: a situation where everything goes wrong at once.
   - _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._
10. In 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.
   - Simple: A group of things in data that are alike and clearly different from the rest.
   - _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._
11. A pronounceable group of consonants occurring together in a word, without a vowel between them.
   - Simple: A group of consonant sounds spoken together with no 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._
12. A logical unit of data storage on a disk, made up of one or more physical sectors.
   - Simple: A unit of space on a computer disk that holds all or part of a file.
   - _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._
13. A batch of bombs or mines let loose at the same time, their explosions combining into a single blast.
   - Simple: A set of bombs or mines that go off together as part of one 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._
14. An ensemble of bound atoms or molecules, especially of a metal, intermediate in size between a single molecule and a bulk solid.
   - Simple: A small group of joined atoms or molecules, bigger than a molecule but smaller than a solid piece.
   - _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._
15. A chord of three or more notes built from seconds, so that adjacent notes sound together.
   - Simple: A chord made of three or more notes that sit right next to each other.
   - _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._
16. A 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. *(US)*
   - Simple: A small metal piece shaped like oak leaves, worn on a medal ribbon for winning the same award again.
   - _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._
17. A sequence of two or more words that occurs with high frequency in a language but is not idiomatic; a lexical bundle.
   - Simple: A short group of words that often appear together in a language, like 'at the end of'.
   - _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._

## Verb

3. To gather or assemble into a close group; to come together in one place.
   - Simple: To come together and form a close group.
   - _Fans cluster outside the stadium hours before each game._
   - _Air bubbles clustered along the edge of the glass._
4. To collect animals, people, objects, or data points into close groups.
   - Simple: To put people or things into close groups.
   - _The florist clustered the white roses at the center of the arrangement._
   - _Researchers cluster the samples by genetic similarity before analysis._
8. To cover with clusters, or to scatter or distribute objects within an area so that they form clusters.
   - Simple: To cover or fill a place with small close groups of things.
   - _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._

## 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.

Source: DictionaryAI, https://dictionaryai.com/define/cluster (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).