salinometer vs hydrometer

salinometer and hydrometer both are nouns.

Word	Noun	Adjective	Verb	Adverb
salinometer	Yes	No	No	No
hydrometer	Yes	No	No	No

As nouns, hydrometer is a hypernym of salinometer; that is, hydrometer is a word with a broader meaning than salinometer:

salinometer: a hydrometer that determines the concentration of salt solutions by measuring their density
hydrometer: a measuring instrument for determining the specific gravity of a liquid or solid

Other hypernyms of salinometer include gravimeter.

salinometer (noun)	hydrometer (noun)
a hydrometer that determines the concentration of salt solutions by measuring their density	a measuring instrument for determining the specific gravity of a liquid or solid