Terminology/naming convention: use of "viscous" vs. "parabolic" or "diffusive"

The term "viscous" is used in some parts of the code where it doesn't specifically refer to the fluid dynamics concept of viscosity, but rather to the mathematical concept of a parabolic PDE (or the more general physical notion of diffusion). Viscosity is specific to fluids, and thus is perhaps less appropriate for other phenomena modelled by parabolic PDEs. The use of the term "viscous" for names beginning with `ViscousFormulation` and `ViscousContainer` is also inconsistent with names like `EquationsParabolic` or `SemidiscretizationHyperbolicParabolic` (or a future `SemidiscretizationParabolic`). Thoughts on changing to `Parabolic` everywhere (`Diffusive` is also an option, but I do not support changing `EquationsParabolic` to `EquationsDiffusive` in that case)?