terpene ter·pene (tûr'pēn')
Any of various unsaturated hydrocarbons in essential oils and certain resins of plants and used in organic syntheses.
Any of a class of hydrocarbons consisting of two or more isoprene (C5H8) units joined together. Simple terpenes are found in the essential oils and resins of plants such as conifers. Turpentine, for example, is such an oil. More complex terpenes include vitamin A, carotenoid pigments (such as lycopene), squalene, and rubber. Terpenes are used in organic synthesis.