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1. Growing close together but not in dense mats
    
2. Clustered together but not coherent
   - agglomerate, agglomerated, agglomerative

1. Come together as in a cluster or flock
   "The poets cluster in this town every summer"
   - constellate, flock, clump
    
2. Gather or cause to gather into a cluster
   "She clustered her fingers into a fist"
   - bunch, bunch up, bundle, clump

See also: clustering, collective, gregarious

Type of: assemble, foregather, forgather, form, gather, meet

Encyclopedia: Cluster