fuel indicator vs indicator

fuel indicator and indicator both are nouns.

Word	Noun	Adjective	Verb	Adverb
fuel indicator	Yes	No	No	No
indicator	Yes	No	No	No

As nouns, indicator is a hypernym of fuel indicator; that is, indicator is a word with a broader meaning than fuel indicator:

fuel indicator (noun)	indicator (noun)
an indicator of the amount of fuel remaining in a vehicle	a device for showing the operating condition of some system
	a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time
	a signal for attracting attention
	(chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction