gasometer vs gas meter

gasometer and gas meter both are nouns.

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

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

gasometer and gas meter: a meter for measuring the amount of gas flowing through a particular pipe

gasometer (noun)	gas meter (noun)
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
a meter for measuring the amount of gas flowing through a particular pipe