Physics Spectrometry refers to the various methods of spectral analysis used in determining the composition and structure of a material.
In practice the term has become synonymous with spectroscopy, the eye being replaced by other detectors and measuring instruments; the visible spectrum is merely one particular field of the spectrum for observation and physical-chemical analysis.
Spectrometry is based on the qualitative and quantitative study of the spectra obtained by the interaction of the material with various radiations such as light and X-rays (cf. crystallography) and electrons.
There is some controversy about the usage of the three terms, spectroscopy, spectrometry and spectrography. In practice the three terms seem to be used somewhat indiscriminately, but there is normally no ambiguity of meaning.