Terpenes are a class of natural products consisting of compounds with the formula (C₅H₈)_n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. In plants, terpenes and terpenoids are important mediators of ecological interactions, while some insects use some terpenes as a form of defense. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control.

टरपीन (Terpene) हाइड्रोकार्बन वर्ग का असंतृप्त यौगिक है, जिसमें केवल कार्बन और हाइड्रोजन तत्व होते है। टरपीन (Terpene) शब्द टरपेंटाइन (turpentine) से निकला है, जिसमें अनेक टरपीन पाए गए हैं।