salinometer vs gravimeter

salinometer and gravimeter both are nouns.

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

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

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

Other hypernyms of salinometer include hydrometer.

salinometer (noun)	gravimeter (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
	a measuring instrument for measuring variations in the gravitational field of the earth