n. [ Ethene + -yl. ] (Chem.) (a) A trivalent hydrocarbon radical, CH3.C. (b) A univalent hydrocarbon radical of the ethylene series, CH2:CH; -- called also vinyl. See Vinyl. [ 1913 Webster ]
n. [ Methene + -yl. ] (Chem.) The hypothetical hydrocarbon radical CH, regarded as an essential residue of certain organic compounds. [ 1913 Webster ]