scale invariance

An object is said to be self-similar if it looks "roughly" the same on any scale. Fractals are a particularly interesting class of self-similar objects. Self-similar objects with parameters N and s are described by a power law such as N = s^d, where d = (ln N)/(ln s) is the "dimension" of the scaling law, known as the Hausdorff dimension.

fractal | Hausdorff dimension