ampere: [19] This international term for a unit of electrical current derives from the name of André-Marie Ampère (1775–1836), the French physicist and mathematician. It was officially adopted by the Congrès Électrique in Paris in 1881. Ampère himself is best remembered for first making the distinction between electrical current and voltage, and for explaining magnetism in terms of electrical currents. The term ammeter ‘current-measuring device’ [19] was based on ampere. [ampere etymology, ampere origin, 英语词源]
1881, "the current that one volt can send through one ohm," from French ampère, named for French physicist André-Marie Ampère (1775-1836). Shortened form amp is attested from 1886.