A positive electrode is an “anode,” a terminal through which the negative charge leaves a cell as the current flows into the cell from the outside. Conversely, a negative electrode is a “cathode,” a terminal through which the negative charge enters a cell as the current flows out.
Electrodes are essential components of electrochemical cells as the movement of electrons across them through oxidation and reduction produces an electric charge. Since they need to be good conductors of electricity, they are usually made of metal and are commonly used in fuel cells, electroplating and grounding. They are also used in medical equipment, such as defibrillators.