bathymeter vs measuring device

bathymeter and measuring device both are nouns.

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

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

bathymeter: an instrument that measures the depth of water
measuring device: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of bathymeter include measuring instrument, measuring system.

bathymeter (noun)	measuring device (noun)
an instrument that measures the depth of water	instrument that shows the extent or amount or quantity or degree of something