ergometer vs measuring device

ergometer and measuring device both are nouns.

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

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

ergometer: measuring instrument designed to measure power
measuring device: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of ergometer include measuring instrument, measuring system.

ergometer (noun)	measuring device (noun)
measuring instrument designed to measure power	instrument that shows the extent or amount or quantity or degree of something