alkylene
/ˈalkɪliːn/Chemistry
noun
An alkene or olefin; a divalent radical or group derived from an alkene by the loss of two hydrogen atoms. Chiefly attributive or as a formative element in names of compounds.
Origin
Late 19th century; earliest use found in Edgar Fahs Smith (1854–1928). From alkyl + -ene, after German Alkylen.