/meth'euh leuh meen", -euhl am"in/ , n. Chem.
any of three derivatives of ammonia in which one or all of the hydrogen atoms are replaced by methyl groups, esp. a gas, CH 5 N, with an ammonialike odor, the simplest alkyl derivative of ammonia and, like the latter, forming a series of salts. Also called monomethylamine .
[ 1840-50; METHYL- + AMINE ]