Isotrophy

You could imagine a slab of isotropic substance (say glass) and you try measuring any mechanical property, (say it is Young 's Modulus) once along an axis parallel to it the slab, and then again along an axis parallel to it. You will end with the same result both ways. And this result is not just limited to just parallel and perpendicular direction. You can try measuring it along any direction you want. You will still get the same result. That is why you can call the solid isotropic.