The definition of an oil is any nonpolar substance that exists as a viscous liquid at ambient temperatures and has the characteristics of being both hydrophobic (meaning it does not mix with water) and lipophilic (and so mixes with other oils).
Different chemical compounds that share these characteristics may be classed as oils, although they may have no other similarities in chemical structure, properties, and uses.
Oils may be animal, vegetable, or petrochemical in origin.
