- In mathematics, a group is a set together with a binary operation satisfying certain algebraic conditions. See group (mathematics).
- In astronomy, a group is a small number of galaxies (up to 50 or so) that are near each other, like the Local Group, which is the group of galaxies we live in. See groups and clusters of galaxies.
- In chemistry, a group is either
- a column in the periodic table of chemical elements; see periodic table group
- a functional entity consisting of certain atoms whose presence provides a certain property to a molecule, e.g. the methyl group; see Functional group.
- In sociology, a group involves a sub-set of a culture or of a society: see group (sociology).