[eth.yl.ene] n (ca. 1852) 1: a colorless flammable gaseous unsaturated hydrocarbon that is found in coal gas, can be produced by pyrolysis of petroleum hydrocarbons, and occurs in plants functioning esp. as a natural growth regulator that promotes the ripening of fruit
2: a divalent hydrocarbon group derived from ethane -- eth.yl.enic adj