Any of a large group of volatile unsaturated hydrocarbons found in the essential oils of plants, especially conifers and citrus trees. They are based on a cyclic molecule having the formula C₁₀H₁₆
- ‘In woody plants, carbon-based chemical compounds such as phenolics and terpenes comprise the main chemical defence.’
- ‘Lactones, phenolic aldehydes (such as vanillin), terpenes (essential oils) and wood tannins are all by-products of oak, so it is understandable that too much can rob a white wine of its fruit and delicacy.’
- ‘Essential oils contain many terpenes, which are rapidly absorbed through the lungs and cross the blood-brain barrier.’
- ‘It is the terpenes that give the resins of conifers their characteristic smells.’
- ‘Air fresheners, for example, often contain limonene - a terpene added to many household products to improve fragrance.’
Late 19th century: from German Terpentin turpentine + -ene.