olefin
noun
- hydrocarbon (cyclic or acyclic but not aromatic) having one or more double bonds
Wiktionary
Pronunciation: /ˈəʊləfɪn/
noun
Etymology: From olefiant, "oil-producing".
- Any of a class of unsaturated open-chain hydrocarbons such as ethylene; an alkene with only one carbon-carbon double bond.