ring mainBrE/ˈrɪŋ meɪn/NAmE/ˈrɪŋ meɪn/noun (specialist) anarrangementofcablesthatallowselectricitytobesuppliedtoaseriesofplacesfromeitheroftwodirections(电路的)环形干线 = ring circuitanarrangementofconnectedpipesthatallowswater, steam, etc. toenterandleaveasystem(管路的)环形主线