Entry 1 sense Webster, 1913 overcoat /ōv'-ẽrk-ōtˌ/ · o·ver·coat · IPA /ˈoʊvɚkoʊt/ 01 n. A coat worn over the other clothing; a greatcoat; a topcoat. 1. A coat worn over the other clothing; a greatcoat; a topcoat.