Real Dictionary

margarine
variable noun: Margarine is a yellow substance made from vegetable oil and animal fats that is similar to butter. You spread it on bread or use it for cooking.

margarine in American English
a spread or cooking fat made of refined vegetable oils (and sometimes rendered animal fat) processed to the consistency of butter, often churned with pasteurized milk, or whey, and generally fortified with vitamins A and D
noun: a butterlike product made of refined vegetable oils, sometimes blended with animal fats, and emulsified, usually with water or milk

margarine in British English
noun: a substitute for butter, prepared from vegetable and animal fats by emulsifying them with water and adding small amounts of milk, salt, vitamins, colouring matter, etc