1886 as an abbreviation of ampere; 1967 as an abbreviation of amplifier.
Entries linking to amp
ampere n.
1881, "the current that one volt can send through a resistance of one ohm," from French ampère, named for French physicist André-Marie Ampère (1775-1836). Adopted by the Electric Congress at Paris in 1881. Shortened form amp is attested from 1886.
amplifier n.
1540s; agent noun from amplify. Electronic sense is from 1914; shortened form amp is from 1967. Alternative stentorphone (1921) did not catch on.