photometer vs measuring system

photometer and measuring system both are nouns.

Word	Noun	Adjective	Verb	Adverb
photometer	Yes	No	No	No
measuring system	Yes	No	No	No

As nouns, measuring system is a hypernym of photometer; that is, measuring system is a word with a broader meaning than photometer:

photometer: measuring instrument for measuring the luminous intensity of a source by comparing it (visually or photoelectrically) with a standard source
measuring system: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of photometer include measuring device, measuring instrument.

photometer (noun)	measuring system (noun)
photographic equipment that measures the intensity of light	instrument that shows the extent or amount or quantity or degree of something
measuring instrument for measuring the luminous intensity of a source by comparing it (visually or photoelectrically) with a standard source