supervoltagePronunciation: /ˌsuːpəˈvəʊltɪdʒ, -ˈvɒltɪdʒ, ˌsjuː-/Definition of supervoltage noun [usually as modifier] Medicine a voltage in excess of 200 kV used in X-ray radiotherapy: supervoltage therapysupervoltage in other Oxford dictionaries Definition of supervoltage in the US English dictionary