Anisotropic (meaning non-isotropic) is usually used to describe a directionally dependent phenomenon.
For example,
This term is also used in the field of computer graphics. For example, an anisotropic surface will change in appearance as it is rotated about its geometric normal, as is the case with velvet. Anisotropic scaling occurs when something is scaled by different amounts in different directions, for example, stretching a 64×64-pixel texture to cover a 12×34-pixel rectangle, this is known as anisotropic filtering.