(organic chemistry) Any chemical entity that is temporarily reacted with a functional group so as to protect it from a subsequent reaction

A group of people joined temporarily to accomplish some task or take part in some organised collective action. / (US military) A component of a naval task force.

(group theory) The projective general linear group mathbf PGL(2,ℂ): the group of Möbius transformations on the Riemann sphere.

Used other than figuratively or idiomatically: see group, theory; a theory about (particular kinds of) groups.

In chemistry, a group of elements with related properties similar to that of platinum, notably high resistance to chemical activity, particularly oxidation and reaction with acids. The platinum group consists of the elements ruthenium, rhodium, palladium, osmium, iridium, and platinum. In the periodic table of the elements they are in period 5 or 6 and in groups 8, 9 or 10.

(physics, mathematics) The group of all Lorentz transformations in spacetime.

(organic chemistry) A specific grouping of elements that is characteristic of a class of compounds, and determines some properties and reactions of that class.

A demographic grouping based on age.

A pop group made up of (usually attractive) young women.

A musical group specializing in pop music.