Why the term "diffraction" in XRD When there is selective reflection of x-rays from crystals, why the phenomena is called "diffraction"? As we know that diffraction is associated with the bending of waves at the corners of any obstacle, here there does not seem to be any bending around the corner. So why the name diffraction? Since it is an interference between the waves emitted from the upper and lower plane of atoms, shouldn't it be called "interference"? Some possible answers can be the following: 1. It is an unfortunate misnomer. (One of my colleagues told me this recently) 2. The idea of diffraction stated above is not correct or we can say it is not accurate. Then how to define "diffraction"?