English Reference
noun · verb

cluster

n. · v.
US /ˈkɫəstɝ/ UK /klˈʌstɐ/ clus·ter UK spelling clusters

  1. 01 B2 Upper Intermediate

    n.a group of similar things or people positioned closely together.

    n.a number of similar things or people growing or grouped together in a compact way.

    Simple

    A small cluster of fans waited outside the hotel to see the singer.

    In context

    The researchers identified a cluster of rare plants growing near the riverbank, suggesting a unique microclimate in that specific area.

  2. 02 C1 Advanced Technical Science

    n.a group of stars, data points, or cases of a disease that appear close together.

    n.a statistically significant grouping of data points, celestial bodies, or medical cases within a specific area or timeframe.

    Simple

    The telescope revealed a bright cluster of stars in the center of the galaxy.

    In context

    Health officials investigated a cluster of respiratory infections reported within the same three-block radius over the last fortnight.

  3. 03 C1 Advanced SlangInformal

    n.a situation where everything goes wrong or is very messy.

    n.a chaotic or poorly managed situation; often used as a polite shortening of a more vulgar term.

    Simple

    The morning commute was a total cluster because of the broken train.

    In context

    The product launch turned into a complete cluster when the servers crashed and the marketing team lost access to their accounts.

    Usage

    Often used in professional environments to avoid using the full vulgar expression 'clusterfuck'.

  4. 04 B2 Upper Intermediate

    v.to form a group or to move close together.

    v.to gather or grow into a cluster; to position objects or data into discrete groups.

    Simple

    The children clustered around the teacher to hear the story.

    In context

    The cottages were clustered at the foot of the hill, protected from the harsh winds blowing off the Atlantic.

At first glance, the site is an unremarkable cluster of tall trees wrapped in thick greenery.

BBC News· 12 Aug 2026

That’s why eye injuries cluster around eclipses even though the sun itself is unchanged.” Jim Diment, assistant manager of Howleys toy shop in Weymouth, models the safety eyewear.

The Guardian· 12 Aug 2026

The noun is derived from Middle English cluster (“bunch, cluster, spray; compact body or mass, ball”) [and other forms], from Old English cluster, clyster (“cluster, bunch, branch”), from Proto-Germanic klas-, klus- (“to clump, lump together”) (possibly from Proto-Indo-European gel- (“to ball up; to clench; to amass”)) + -þrą (suffix forming nouns denoting an instrument or tool). The English word is probably a doublet of clot. The verb is derived from the noun. Cognates * Dutch klister (“cluster”) (dialectal) * Icelandic klasi (“cluster; bunch of grapes”) * Low German Kluuster (“cluster”) * Swedish kluster (“cluster”)

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin ine-pro *gel-
Level C1 · Advanced
Frequency Frequent
Updated