Real Dictionary

methylamine in American English
a colorless, flammable gas, CH3NH2, that smells like ammonia and is usually prepared synthetically by heating methanol with ammonia under pressure in the presence of a catalyst: it is used in the manufacture of dyes, pharmaceuticals, insecticides, etc.
noun: any of three derivatives of ammonia in which one or all of the hydrogen atoms are replaced by methyl groups, esp. a gas, CH5N, with an ammonialike odor, the simplest alkyl derivative of ammonia and, like the latter, forming a series of salts

methylamine in British English
noun: a colourless flammable water-soluble gas, used in the manufacture of herbicides, dyes, and drugs. Formula: CH3NH2