fuel indicator(n = noun.artifact) fuel gauge - an indicator of the amount of fuel remaining in a vehicle;
is a kind of indicator
is a part of fuel system

absorption indicator, acid-base indicator, diesel fuel, flight indicator, fossil fuel, fuel, fuel cell, fuel consumption rate, fuel filter, fuel gauge, fuel injection, fuel injection system, fuel level, fuel line, fuel oil, fuel pod, fuel system, indicator, indicator lamp, leading indicator, nuclear fuel, oxidation-reduction indicator, rocket fuel, speed indicator, torsion indicator, turn indicator