Definition: Wavenumber, in physics and particularly in optics, refers to the number of waves passing through a unit area per unit time. It is often denoted with the letter "n" or "ω". In optics, it represents the frequency at which light waves are observed. For example, if you shine a laser on a glass plate (or any other reflective surface), you can observe the light waves as a continuous stream of light passing through the plate. The wavenumber is used to describe