cluster

1 of 2

noun

clus·​ter ˈklə-stər 

: a number of similar things that occur together: such as

a

: two or more consecutive consonants or vowels in a segment of speech

b

: a group of buildings and especially houses built close together on a sizable tract in order to preserve open spaces larger than the individual yard for common recreation

c

: an aggregation of stars or galaxies that appear close together in the sky and are gravitationally associated

the Perseus cluster of galaxies

d

: a larger than expected number of cases of disease (such as leukemia) occurring in a particular locality, group of people, or period of time

e

: a number of computers networked together in order to function as a single computing system

Consisting of groups of inexpensive machines cobbled together, clusters in many ways have supplanted traditional supercomputers.

—Elizabeth K. Wilson

clustery

ˈklə-st(ə-)rē 

adjective

cluster

2 of 2

verb

clustered; clustering ˈklə-st(ə-)riŋ 

transitive verb

1

: to collect into a cluster

cluster the tents together

2

: to furnish with clusters

The bridge was clustered with men and officers …

—Herman Wouk

intransitive verb

: to grow, assemble, or occur in a cluster

they clustered around the fire

Synonyms of cluster

Noun

• batch
• array
• collection
• constellation
• bunch
• grouping
• group
• assemblage
• set
• clump
• package
• battery
• lot

Verb

• gather
• converge
• rendezvous
• meet
• assemble
• conglomerate
• convene
• congregate
• get together

Examples of cluster in a Sentence

Noun

a cluster of cottages along the shore

A small cluster of people had gathered at the scene of the accident.

Verb

The children clustered around the storyteller.

the mice clustered together into a small burrow

Recent Examples on the Web

Noun

Across the Pittsburgh area, there have been approximately 81 storm reports from this afternoon's linear cluster of storms. — Trey Fulbright, CBS News, 16 Aug. 2026

Suckers that grow in clusters from higher up on the trunk or along branches are called water sprouts and may also be a sign of stress. — Beth Botts, Chicago Tribune, 16 Aug. 2026

Verb

Sacramento was crawling Saturday as crowds packed Bugtopia, winding between tables and clustering around displays with the restless motion of a human-sized ant colony. — Naomi Taxay, Sacbee.com, 15 Aug. 2026

Nanda Win, head of the Yangon Regional Department of Public Health, said cases were particularly concentrated in downtown Yangon’s Chinatown area, where street food vendors, restaurants and bars are clustered, according to the report. — ABC News, 14 Aug. 2026

Word History

Etymology

Noun and Verb

Middle English, from Old English clyster; akin to Old English clott clot

First Known Use

Noun

before the 12th century, in the meaning defined above

Verb

14th century, in the meaning defined at transitive sense 1

Phrases Containing cluster

• cluster analysis
• cluster bomb
• cluster headache
• globular cluster
• inter-cluster
• oak-leaf cluster
• sub-cluster

Rhymes for cluster

• bluster
• buster
• duster
• juster
• luster
• lustre
• maister
• muster
• thruster
• trustor
• adjuster
• baluster

Kids Definition

cluster

1 of 2 noun

clus·​ter ˈkləs-tər 

: a number of similar things growing, collected, or grouped together : bunch

a cluster of houses

a flower cluster

cluster

2 of 2 verb

clustered; clustering -t(ə-)riŋ 

: to grow, collect, or gather in a cluster

Medical Definition

cluster

noun

clus·​ter ˈkləs-tər 

: a larger than expected number of cases of disease (as leukemia) occurring in a particular locality, group of people, or period of time