olefin

n.	1.	(Chem.) Olefiant gas, or ethylene. See Ethylene.
	2.	(Chem.) Any one of the series of unsaturated hydrocarbons of which ethylene is the type; a member of the alkene series of hydrocarbons; an alkene.

Noun

1.

olefin - any unsaturated aliphatic hydrocarbon Synonyms: alkene, olefine

aliphatic compound, alkene, ethene, ethylene, olefine