An Animated UV is an option with HeroMaterials in 3ds Max or Maya. U and V are coordinates which apply to how a 2-dimensional texture is applied to a 3-dimensional mesh. An artist can "animate" UVs by setting them to scroll at specified speeds, so that the applied texture will appear to move on the mesh surface. There is also a second animated layer option to add depth to textures containing alpha transparency. This feature is useful for creating such things as waterfall effects, moving molten lava, or moving conveyor belts without the need to rely on mesh animation.
For example, if an artist animated the U coordinates of a 2D texture, the texture would appear to slide along the local X axis of the mesh