Spectrometry

Spectrometry is the measurement of the interactions between light and matter, and the reactions and measurements of radiation intensity and wavelength. In other words, spectrometry is a method of studying and measuring a specific spectrum, and it’s widely used for the spectroscopic analysis of sample materials. It’s the practical application where results are generated, helping in the quantification of, for example, absorbance, optical density or transmittance.

ref: https://www.atascientific.com.au/spectrometry/