oil: [12] Around the Mediterranean in ancient times the only sort of oil encountered was that produced by pressing olives, and so ‘oil’ was named after the olive. The Greek word for ‘olive’ was elaíā, and from it was derived elaíon ‘olive oil’. This passed into Latin as oleum, and reached English via Old French oile. By now it had begun to be applied to similar substances pressed from nuts, seeds, etc, but its specific modern use for the mineral oil ‘petroleum’ is a much more recent, essentially 19th-century development. => olive
oil (n.)
late 12c., "olive oil," from Anglo-French and Old North French olie, from Old French oile, uile "oil" (12c., Modern French huile), from Latin oleum "oil, olive oil" (source of Spanish, Italian olio), from Greek elaion "olive tree," from elaia (see olive). Old English æle, Dutch olie, German Öl, etc. all are from Latin. It meant "olive oil" exclusively till c. 1300, when meaning began to be extended to any fatty, greasy substance. Use for "petroleum" first recorded 1520s, but not common until 19c. The artist's oils (1660s), short for oil-color (1530s), are paints made by grinding pigment in oil.
oil (v.)
mid-15c., from oil (n.). Related: Oiled; oiling. An Old English verb in this sense was besmyrian.