meth(o)-

The methyl radical, —CH₃.

English methylene, derived from Greek methu, wine, plus hulē, wood, because methyl alcohol was first prepared by the destructive distillation of wood.

Meth‑ occurs in a variety of common names for chemical substances, many of them drugs, such as methamphetamine, a methyl derivative of amphetamine, a synthetic drug used illegally as a stimulant; methadone, used in the treatment of morphine and heroin addiction; and methicillin, a semi-synthetic form of penicillin. Examples of drug names on invented stems that include the longer form metho‑ are methoserpidine, used to lower blood pressure; and methotrexate, a treatment for leukaemia. Methene (see ‑ene¹) is the systematic name for the methylene radical —CH₂—; methacrylic acid is used in the manufacture of synthetic resins.