Invariant may have several meanings, among which are: Invariant (computer science), an expression whose value doesn't change during program execution In computer science, a type in overriding that's neither covariant nor contravariant Invariant (mathematics), something unaltered by a transformation, for example: taking a homotopy group functor on the category of topological spaces. Then, homomeomorphic spaces have isomorphic fundamental group. See topological invariant. Invariant (music) In… (More on Invariant)