skeumorphic design is usually digital, it can help create a feeling of familiarity.
True skeumorphic design imitates real world looking items. A computer desktop screen that looks like a real office desktop is an extreme example. A computer calendar with what appears to be real leather bounding is another.
It has morphed into including a design that has a cluttered look, using real world items like flames of fire even if they are sort of cartooned.
When talking about the latter you will hear terms like "flattening the design" to get away from skeumorphism