Webster’s Revised Unabridged Dictionary · 1913
Propylene
Pro′pyl·ene (prō′pĭl·en), n. [Cf. F. propylène.] (Chem.) A colorless gaseous hydrocarbon (C3H6) of the ethylene series, having a garlic odor. It occurs in coal gas, and is produced artificially in various ways. Called also propene.