methylene (n.)

1835, from French méthylène (1834), coined by Jean-Baptiste-André Dumas (1800-1884) and Eugène-Melchior Péligot (1811-1890) from Greek methy "wine" (see mead (n.1)) + hyle "wood" + Greek name-forming element -ene. So called because detected in wood alcohol. "The breakdown of methylene into methyl and -ene, and the identification of the last syllable of methyl with the general suffix -ly, led to the use of meth- as a separate combining-element, as, for example, in methane, methacrylic" [Flood].