Where Edison’s power came from. It’s a step up from what was called, no lie, an iron-clad machine.
Today, we use alternating current. (Go ahead, click that link. It lets you play with the controls on a virtual generator to mess around with waveforms. It’s fun.)
Image from Webster’s New International Dictionary of the English Language, 1911, G & C Miriam Co. Springfield, MA, found here.