oil1/ɔIl; ɔIl/n [U] 1 a thick dark liquid from under the ground, used to make petrol 石油﹐原油: the price of oil 油价oil companies 石油公司2 a thick liquid used to make the parts of machines move more easily〔用于机器的〕润滑油: engine oil 机油3 a liquid that comes from plants or animals, used especially in cooking〔尤用于烹调的〕植物油,动物油: cooking oil 食用油vegetable/olive/sunflower oil tuna in olive oil 橄榄油浸吞拿鱼CRUDE OIL, ESSENTIAL OIL