essential oil n.
A volatile oil, usually having the characteristic odor or flavor of the plant from which it is obtained, used to make perfumes and flavorings.
|essential oil (ĭ-sěn'shəl) Pronunciation Key
Any of various volatile liquids, such as rose oil or lavender oil, that have a characteristic odor and are produced by plants. Essential oils are composed primarily of terpenes and of lesser quantities of alcohols, aldehydes, esters, phenols, and other compounds that impart particular odors or flavors. They are used to make perfumes, soaps, flavorings, and other products.