gage vs petrol gage

gage and petrol gage both are nouns.

Word	Noun	Adjective	Verb	Adverb
gage	Yes	No	Yes	No
petrol gage	Yes	No	No	No

As nouns, petrol gage is a hyponym of gage; that is, petrol gage is a word with a more specific, narrower meaning than gage:

gage: a measuring instrument for measuring and indicating a quantity such as the thickness of wire or the amount of rain etc.
petrol gage: gauge that indicates the amount of gasoline left in the gasoline tank of a vehicle

gage (noun)	petrol gage (noun)
a measuring instrument for measuring and indicating a quantity such as the thickness of wire or the amount of rain etc.	gauge that indicates the amount of gasoline left in the gasoline tank of a vehicle
street names for marijuana

gage (verb)	petrol gage (verb)
place a bet on