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

North Korea conducted a series of tests last week that state media said involved various new weapons systems, including ballistic missiles armed with cluster-bomb warheads, while its senior officials issued crude statements ridiculing South Korean hopes for warmer relations. —ABC News, 13 Apr. 2026

The roots of the plant consist of a cluster of rhizomes (swollen underground stems with feeder roots attached). —Steve Bender, Southern Living, 13 Apr. 2026

Verb

Viacheslav Onyshchenko/Global Images Ukraine via Getty Images Worshippers clustered outside wooden churches to take part in the annual blessing of baskets for the holiday table. —CBS News, 12 Apr. 2026

Worshipers clustered outside wooden churches to take part in the annual blessing of baskets for the holiday table. —Derek Gatopoulos, Los Angeles Times, 12 Apr. 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
• muster
• thruster
• trustor
• adjuster
• baluster
• blockbuster

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