|Origin:||oile, from Latin oleum 'olive oil', from Greek elaia 'olive'|
a smooth thick liquid that is used to make machines run easily or is burned to produce heat:
Check the oil level in your car every week.
The heating system runs on oil.
the thick, dark liquid from under the ground from which petrol is produced [↪ crude]:
natural substance under the ground[uncountable]TPGTI
a rise in the price of oil
a smooth, thick liquid made from plants or some animals, used especially in cooking or for making beauty products: ➔ castor oil, cod-liver oil, linseed oil
liquid from plants[uncountable and countable]DFCDCB
coconut oil shampoo
Fish oils are supposed to help relieve arthritis.
paints that contain oil [= oil paints]
I usually paint in oils (=using oils).