I. noun — [ mass noun] 1. a synthetic, addictive, mood-altering drug, used illegally as a stimulant • the amphetamine put him on a high for an hour
• [ count noun]
he was jailed for three months for possessing amphetamines.
●Chem. formula: C6H5CH2CH(CH3)NH2.
– origin 1930s: abbreviation of its chemical name, a(lpha-)m(ethyl) phe(ne)t(hyl)amine.