Elsewhere on the mountainside, Ezra was driving the horses homeward. The big Suffolk mares were anticipating the storm to come and were directed toward the homestead and pulled accordingly. With a hurried trot they turned the last corner and their reinleader stirred them to a lope. Fallen tree in tow, destined to burn. Horses, teamster, iron and fuel under darkening skies moved like an old funeral procession through a crowd clapping little shadows in and out of existence. Ezra is fauna.
An isotropic material is one which looks the same in every direction. We cannot define any special direction using the material properties. In other words, none of the properties depend the orientation; it is perfectly rotationally symmetric. Note that in order to be isotropic the material must be homogenous on the length scale of interest, ie the same at every point in the material.
For instance, rubber is a very isotropic material. Take a rubber ball, and it will feel the same and bounce the same however you rotate it. On the other hand, wood is an anisotropic material: hit it with an axe and it will take more force to break of you are cutting across the grain than along it. (Remember we're thinking about the material rather than the shape of the object.)