isotropic and anisotropic

isotropic: Properties of a material are identical in all directions

anisotropic: Properties of a material depend on the direction; for example, wood. In a piece of wood, you can see lines going in one direction; this direction is referred to as "with the grain". The wood is stronger with the grain than "against the grain". Strength is a property of the wood and this property depends on the direction; thus it is anisotropic.