(economics, sociology) A group in a given population having an income within a specified range.

(US) A small geographical unit that is part of the US censuses

(group theory) The group of automorphisms of a given set or other mathematical object, with the group operation being function composition.

A group of musicians who regularly perform together.

(dated, psychotherapy) A gathering of people who intentionally meet and interact so that each member may improve his or her ability both to express feelings and to react with appropriate sensitivity to the feelings of others.

(medicine) The basic system of categorizing blood by antigen type.

(inorganic chemistry) Group 3 of the periodic table, comprising scandium, yttrium, lanthanum and actinium.

(inorganic chemistry) Group 4 of the periodic table, comprising titanium, zirconium, hafnium and rutherfordium

(astronomy) A group of galaxies that hold together gravitationally.

(group theory) a group of symmetries of a regular polygon