From Longman Dictionary of Contemporary Englishalternating currentˌalternating ˈcurrent noun [uncountable] TPE (abbreviation AC) a flow of electricity that changes direction regularly and quickly → direct current
Examples from the Corpus
alternating current• Tesla was told firmly that he must never so much as mention the subject of alternating current.• The Westinghouse Company was badly overextended because of the expensive campaign to put the coun-try on a system of alternating current.• Unlike Edison, Westinghouse was a convert to alternating current.• The design could be improved, he declared, by switching to alternating current.• The change of attitude towards alternating current was certainly helped by the Westinghouse exhibit at the Columbian Exposition that year. 