methylene

noun

Etymology: Etymology tree French méthylène English methylene French méthylène, from Ancient Greek μέθυ (méthu, “wine”) + ὕλη (húlē, “wood”). By surface analysis, meth- + -ylene.

1. The divalent group –CH₂– in which the free valencies are part of single bonds.
2. The same group, present as a repeating unit, in aliphatic compounds with names such as hexamethylenediamine.
3. The unstable carbene :CH₂