The Collaborative International Dictionary of English v.0.48:

Cluster \Clus"ter\, v. t.
   To collect into a cluster or clusters; to gather into a bunch
   or close body.
   [1913 Webster]

         Not less the bee would range her cells, . . .
         The foxglove cluster dappled bells.      --Tennyson.
   [1913 Webster]

         Or from the forest falls the clustered snow. --Thomson.
   [1913 Webster]

   Clustered column (Arch.), a column which is composed, or
      appears to be composed, of several columns collected
      together.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cluster \Clus"ter\ (kl[u^]s"t[~e]r), n. [AS. cluster, clyster;
   cf. LG. kluster (also Sw. & Dan. klase a cluster of grapes,
   D. klissen to be entangled?.)]
   1. A number of things of the same kind growing together; a
      bunch.
      [1913 Webster]

            Her deeds were like great clusters of ripe grapes,
            Which load the bunches of the fruitful vine.
                                                  --Spenser.
      [1913 Webster]

   2. A number of similar things collected together or lying
      contiguous; a group; as, a cluster of islands. "Cluster of
      provinces." --Motley.
      [1913 Webster]

   3. A number of individuals grouped together or collected in
      one place; a crowd; a mob.
      [1913 Webster]

            As bees . . .
            Pour forth their populous youth about the hive
            In clusters.                          --Milton.
      [1913 Webster]

            We loved him; but, like beasts
            And cowardly nobles, gave way unto your clusters,
            Who did hoot him out o' the city.     --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cluster \Clus"ter\, v. i. [imp. & p. p. Clustered; p. pr. &
   vb. n. Clustering.]
   To grow in clusters or assemble in groups; to gather or unite
   in a cluster or clusters.
   [1913 Webster]

         His sunny hair
         Cluster'd about his temples, like a god's. --Tennyson.
   [1913 Webster]

         The princes of the country clustering together. --Foxe.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cluster
    n 1: a grouping of a number of similar things; "a bunch of
         trees"; "a cluster of admirers" [syn: bunch, clump,
         cluster, clustering]
    v 1: come together as in a cluster or flock; "The poets
         constellate in this town every summer" [syn: cluster,
         constellate, flock, clump]
    2: gather or cause to gather into a cluster; "She bunched her
       fingers into a fist" [syn: bunch, bunch up, bundle,
       cluster, clump]

Moby Thesaurus II by Grady Ward, 1.0:

187 Moby Thesaurus words for "cluster":
   accumulate, adhere, agglomerate, agglomeration, aggregate, aggroup,
   amass, army, array, assemblage, assemble, assembly, associate,
   band, batch, bevy, block, body, breccia, bring together, bulk,
   bunch, bunch together, bunch up, bundle, cake, clabber, clasp,
   cleave, clinch, cling, cling to, clot, clump, clutch, coagulate,
   cohere, cohue, collect, collection, colligate, collocate, combine,
   come together, company, compare, compile, concrete, concretion,
   congeal, conglomerate, conglomeration, congregate, congregation,
   converge, copse, copulate, corral, couple, covey, crew, crop,
   crowd, crush, cumulate, curd, curdle, date, deluge, dig up,
   draw together, dredge up, drive together, embrace, flock,
   flock together, flood, flow together, forgather, freeze to, fuse,
   galaxy, gang around, gang up, gather, gather around, gather in,
   gather together, gathering, gel, gelatinate, gelatinize, get in,
   get together, grasp, group, grouping, groupment, grove,
   grow together, hang on, hang together, hassock, heap,
   herd together, hive, hold, hold on, hold together, horde, host,
   huddle, hug, incrassate, inspissate, jam, jell, jellify, jelly,
   join, juxtapose, knot, league, legion, link, lopper, lot, lump,
   lump together, make up, mass, match, meet, merge, mess, mill, mob,
   mobilize, multitude, muster, node, package, pair, panoply, parcel,
   partner, party, persist, press, put together, rabble, raise,
   rake up, rally, rally around, rendezvous, round up, rout, ruck,
   scrape together, seethe, set, shock, slew, solid, solid body,
   solidify, spate, stay, stay put, stick, stick together, stook,
   stream, surge, swarm, take hold of, take up, thick, thicken,
   thicket, throng, tuft, tussock, unite, whip in, wisp



The Free On-line Dictionary of Computing (30 December 2018):

cluster
clustering

   1.  Multiple servers providing the same
   service.  The term may imply resilience to failure and/or
   some kind of load balancing between the servers.  Compare
   RAIS.

   2.  An elementary unit of allocation of a disk
   made up of one or more physical blocks.

   A file is made up of a whole number of possibly
   non-contiguous clusters.  The cluster size is a tradeoff
   between space efficiency (the bigger is the cluster, the
   bigger is on the average the wasted space at the end of each
   file) and the length of the FAT.

   (1996-11-04)