alkene
noun [ C ] chemistry specialized uk/ˈæl.kiːn/ us/ˈæl.kiːn/
烯烃，链烯（双链链接碳氢化合物）
any gas in a group that contains carbon and hydrogen atoms, with the carbon atoms joined together in a double bond
Ethene and propene are alkenes. 乙烯和丙烯都是烯烃。