Anisotropy : The ability of crystalline solids to change their physical properties when measured in different directions is called anisotropy.
Explanation : This property is due to different arrangement of constituents in different directions. Different types of particles fall on the way of measurements in different directions. Hence the composition of crystalline solid changes with directions changing their physical properties.

Anisotropy in crystals : Different arrangements of constituent particles about different directions, AB, CD and EF.