Wavelength
From Glossary of Meteorology
wavelength
In radiation, the distance between periodic spatial repetitions of an electromagnetic wave at a given instant of time; used extensively to classify the nature of the radiation, since most of the interactions between radiation and matter are extremely sensitive to the wavelength of the radiation.
Units are length (e.g., nm, μm, mm, cm, with conventional usage depending on which part of the electromagnetic spectrum is being considered).
