a. [ Hydro-, 1 + electric. ] Pertaining to, employed in, or produced by, the evolution of electricity by means of a battery in which water or steam is used. [ 1913 Webster ]

Hydro-electric machine (Physics), an apparatus invented by Sir William Armstrong of England for generating electricity by the escape of high-pressure steam from a series of jets connected with a strong boiler, in which the steam is produced. [ 1913 Webster ]