From Latin 'petra' (rock) + 'oleum' (oil) via French — literally 'rock oil,' distinguishing it from plant and animal oils.
A light fuel oil obtained by distilling petroleum, used in internal combustion engines (British English for gasoline).
From French 'pétrole,' from Medieval Latin 'petroleum' (rock oil), from Latin 'petra' (rock) + 'oleum' (oil). 'Petroleum' literally means 'rock oil' — oil that seeps from rocks, as opposed to vegetable or animal oil. Key roots: petra (Greek/Latin: "rock, stone"), oleum (Latin: "oil").
Petrol is rock juice. 'Petra' (rock) + 'oleum' (oil) = petroleum = oil from rocks. The same 'petra' gives us 'petrify' (turn to stone), Saint 'Peter' (the 'rock' on which the church was built), and 'parsley' (from Greek 'petroselinon,' rock-celery). Meanwhile Americans say 'gasoline,' which comes from 'gas' + the chemical suffix '-ine' — a completely different naming strategy