gas holder vs gasometer

gas holder and gasometer both are nouns.

Word	Noun	Adjective	Verb	Adverb
gas holder	Yes	No	No	No
gasometer	Yes	No	No	No

As nouns, gas holder and gasometer are synonyms defined as:

gas holder and gasometer: a large gas-tight spherical or cylindrical tank for holding gas to be used as fuel

gas holder (noun)	gasometer (noun)
a large gas-tight spherical or cylindrical tank for holding gas to be used as fuel	a large gas-tight spherical or cylindrical tank for holding gas to be used as fuel
	a meter for measuring the amount of gas flowing through a particular pipe