-pəˌnēn noun
( -s )
Etymology: International Scientific Vocabulary terpin + -ene
: any of three liquid isomeric monocyclic terpene hydrocarbons C 10 H 16 obtained usually in mixtures of the alpha and gamma isomers (as by isomerization of pinene, alpha-phellandrene, or dipentene with sulfuric acid): as
a. : the isomer that has an odor like that of lemons and is the principal component of the mixtures and that occurs in coriander oil, chenopodium oil, and other essential oils; 1,3- para -mentha-diene — called also alpha-terpinene
b. : the isomer that occurs in coriander oil, lemon oil, and other essential oils; 1,4- para -menthadiene — called also crithmene, gamma-terpinene