The chemical compound pinene is a bicyclic terpene (C10H16, 136.24 g/mol ) known as a monoterpene. There are two structural isomers found in nature: α-pinene and β-pinene. As the name suggests, both forms are important constituents of pine resin; they are also found in the resins of many other conifers, and more widely in other plants. Both are also used by many insects in their chemical communication system.
Systematic names are (1S,5S)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene and (1S,5S)-6,6-dimethyl-2-methylenebicyclo[3.1.1]heptane.