Invariant (physics)
IN MATHEMATICS AND THEORETICAL PHYSICS, PROPERTY OF A SYSTEM WHICH REMAINS UNCHANGED UNDER SOME TRANSFORMATION
Invariance (physics); Invariant quantity
In theoretical physics, an invariant is an observable of a physical system which remains unchanged under some transformation. Invariance, as a broader term, also applies to the no change of form of physical laws under a transformation, and is closer in scope to the mathematical definition.