An<unk>  is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte or a vacuum). The word was coined by the scientist Michael Faraday from the Greek words elektron (meaning amber, from which the word electricity is derived) and hodos, a way.
Electrode
Semiconductor
Electrostatics
Electron
Electric current
Filter 
Fluid
Fluence