sonometer vs measuring device

sonometer and measuring device both are nouns.

Word	Noun	Adjective	Verb	Adverb
sonometer	Yes	No	No	No
measuring device	Yes	No	No	No

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

sonometer: an instrument used to measure the sensitivity of hearing
measuring device: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of sonometer include measuring instrument, measuring system.

sonometer (noun)	measuring device (noun)
an instrument used to measure the sensitivity of hearing	instrument that shows the extent or amount or quantity or degree of something