(mathematics, geometry, group theory) Any of a class of groups whose finite cases are precisely the finite reflection groups (including the symmetry groups of polytopes), but which are more varied in their infinite cases, and whose range of application encompasses various areas of mathematics.

(biology, evolution) A form of natural selection whereby traits that may be disadvantageous to the individual can be propagated when they are advantageous to the survival of a group as a whole.

a group of people who are approximately the same age and status, especially if they have the same interests

plural of Weyl group

(mathematics) A subgroup of the isometry group of a root system, generated by reflections through the hyperplanes orthogonal to the roots.

plural of silica group

plural of sporadic group

plural of T-group

(phylogenetics) A paraphyletic group consisting of an ancestor and all its descendants, excluding the living representatives of a collection of species.

(US, law) Any of the functionally equivalent chemical entities referenced in a Markush claim.