Wiktionary
monoterpene
n. (context organic chemistry English) any terpene formed from two isoprene units, and having ten carbon atoms; either hydrocarbons such as pinene, or compounds with functional groups such as camphor
Wikipedia
Monoterpene
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula CH. Monoterpenes may be linear (acyclic) or contain rings. Biochemical modifications such as oxidation or rearrangement produce the related monoterpenoids.