engine oil level indicator

engine oil reservoir / engine oil tank

engine capacity / engine power, engine output

instantaneous vertical speed indicator / instantaneous vertical-speed indicator (IVSI)

main gear box oil temperature indicator

fuel level indicator

oil gauge / oil-gauge

oil-level gage

add-oil level

engine detonation indicator

engine vibration indicator

depot maintenance (beyond O and I level activities, performed in an industrial-type facility) / D-level maintenance

all purpose engine oil

engine lubricating oil

engine oil conditioner

engine oil supply passages

heavy oil engine

engine oil

viscous engine oil

reaction engine / motor (jet engine)

rotary engine (Wankel engine)

engine ground run / engine test

air-flow indicator

artificial horizon (gyro horizon/ attitude indicator)

desiccant indicator

gyro course indicator

indicator console

indicator lamp

indicator light

indicator system

performance indicator

radiac computer-indicator

range height indicator (RHI) scope