Spectrometer vs Spectrometry vs Spectroscopy
Long time ago, I wrote mass spectroscopy, by mistake, in an undergraduate exam and the instructor told me "You were the only one in my class who wrote mass spectroscopy." The explanation was that MS is mass spectrometry because it does not deal with light or electromagnetic radiation and that's what the textbook said. At that time internet was not that common. Now I searched the term "mass spectroscopy" in papers using Google Scholar and there are 1,100,000 results with this exact phrase. There are 2,330,000 results for mass spectrometry.

It seems, given the usage, and the difference is not that strict. Consulting the controller of all  chemical terminologies, IUPAC says

https://goldbook.iupac.org/terms/view/S05848


  The study of physical systems by the electromagnetic radiation with
  which they interact or that thay [spelling mistake] produce. Spectrometry is the
  measurement of such radiations as a means of obtaining information
  about the systems and their components. In certain types of optical
  spectroscopy, the radiation originates from an external source and is
  modified by the system, whereas in other types, the radiation
  originates within the system itself.


You will see famous books, especially by Griffiths with the title "Fourier Transform Infrared Spectrometry" and nobody raised an eyebrow.