What is diffraction? Who discovered it? What kind of waves exhibit the diffraction phenomenon?

(N/A) The bending of waves around the corners of an obstacle or through an aperture is called diffraction.
Accurate definition: Diffraction is the physical effect produced by the limited part of a wavefront.
Diffraction was first discovered by the scientist Francesco Maria Grimaldi.
Diffraction occurs in all types of waves,including sound waves,light waves,water waves,and matter waves.
Diffraction depends on the ratio of the wavelength of the wave $\lambda$ to the width of the slit $d$,denoted as $\frac{\lambda}{d}$.
Due to diffraction,light spreads into the geometric shadow region of an opaque object,creating dark and bright fringes.
Optical instruments like telescopes and microscopes have a limit on their resolving power due to diffraction.
The iridescent colours appearing on a $CD$ are due to diffraction effects.
Diffraction is explained by wave theory and is categorized into two types based on the wavefront incident on the slit:
$(i)$ If spherical wavefronts are incident on the slit,it is called Fresnel diffraction.
$(ii)$ If plane wavefronts are incident on the slit,it is called Fraunhofer diffraction.