obse - over
- oil break switch
- oil can / cup
- oil carbon
- oil circuit breaker
- oil clutch
- oil cooler
- oil corrosion
- oil dope
- oil drain
- oil drowned
- oil extractor
- oil face
- oil field
- oil filler
- oil film
- oil filter / screen / strainer
- oil foaming
- oil fuel
- oil gauge
- oil groove
- oil header
- oil heater
- oil immersion
- oil interceptor
- oil layer
- oil level
- oil level gauge
- oil manifold
- oil mist
- oil oxidation stability
- oil oxidation stabilizer
- oil paint
- oil pan / sump
- oil pot
- oil pressure gauge / indicator
- oil proof / resistant / resisting
- oil proofness / resistance
- oil purifier / rectifier
- oil radiator
- oil receiver
