(mathematics) A group of isometries leaving a fixed point.

(chemistry) a vertical series of elements in the periodic table that have three valence electrons; boron is a metalloid, while aluminium, gallium, indium and thallium are metals

A group of people, sampled from a larger population, interviewed in open session for market research or political analysis.

plural of ethnic group

A collection of humans or animals who share certain characteristics, interact with one another, accept expectations and obligations as members of the group, and share a common identity.

plural of splinter group

A group of members of a political party or of a similar organisation who have decided to create their own organisation.

(US, Canada) A collection of residents representing a geographic or otherwise connected residential or business area who together ensure that their communities development interests are known, represented and supported.

plural of support group

(topology) Any group that is a smooth manifold and whose group operations are differentiable.