to cause (a beam of light) to become a set of light and dark or coloured bands in passing by the edge of an opaque body, through narrow slits, etc
diffraction noun
diffractive /-tiv/ adj
diffractively /-tivli/ adv
diffractiveness /-tivnəs/ noun
[Latin diffraction-, diffractio, from diffringere to break apart, from dis- + frangere to break]