- 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
- In sociology, a group involves a sub-set of a culture or of a society: see group (sociology).