Entry 1 sense Webster, 1913 Alternator /ôl'-tẽrn-ātˌ-ẽr/ · Al·ter·na·tor · IPA /ˈɔltərnˌeɪtər/ 01 n. An electric generator or dynamo for producing alternating currents. 1. An electric generator or dynamo for producing alternating currents.(Elec.)