An advocacy group.

(inorganic chemistry) Group seven of the periodic table, comprising manganese, technetium, rhenium and bohrium.

(inorganic chemistry) Group 11 of the periodic table, comprising copper, silver, gold and roentgenium

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

(mathematics) A group of Lie type over a finite field constructed from an exceptional automorphism of a Dynkin diagram that reverses the direction of the multiple bonds, generalizing the Suzuki group.

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

(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.

(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.

A group adding impetus or spirit on a particular topic, especially within a political party or other organization.

(mathematics, geometry, algebra) A group whose elements are all the transformations under which a given object remains invariant and whose group operation is function composition.