An Etymological Dictionary of Astronomy and Astrophysics

1a) Any collection or assemblage of persons or things considered together or regarded as belonging together; e.g. → Local Group of galaxies.

1b) Math.: A set of elements a, b, c, …, finite or infinite in number, with a rule for combining any two of them to form a “product,” subject to the following four axioms: → closure axiom, → associative axiom, → identity axiom, and → inverse axiom.

2a) (v.tr.) To place or associate together in a group.
2b) (v.intr.) To be part of a group.

Etymology (EN): From Fr. groupe “cluster, group,” from It. gruppo “cluster, packet, knot,” likely from P.Gmc. *kruppa “round mass, lump.”

Etymology (PE): Goruh “group,” from Mid.Pers. grôh “group, crowd.”