Anisotropy is the property of being directionally dependent, as opposed to
isotropy, which implies identical properties in all directions. It can be defined as a difference, when measured along different axes, in a material's physical or mechanical properties (
absorbance,
refractive index,
conductivity,
tensile strength, etc.) An example of anisotropy is the light coming through a
polarizer. Another is
wood, which is easier to split along its
grain than against it.