Cluster
Old English clyster ; probably related to clot.
wiktionary
From Middle English cluster, from Old English cluster, clyster(“cluster, bunch, branch”), from Proto-Germanic *klus-, *klas-(“to clump, lump together”) + Proto-Germanic *-þrą(instrumental suffix), related to Low German Kluuster(“cluster”), dialectal Dutch klister(“cluster”), Swedish kluster(“cluster”), Icelandic klasi(“cluster; bunch of grapes”).
etymonline
cluster (n.)
Old English clyster "a number of things growing naturally together," probably from the same root as clot (n.). Meaning "a number of persons, animals, or things gathered in a close body" is from c. 1400. Of stars, from 1727. Cluster-bomb attested by 1950.
cluster (v.)
late 14c. (transitive), "to collect into a cluster or group," from cluster (n.). Intransitive sense, "to form or constitute a cluster," is from 1540s. Related: Clustered; clustering.
