An electrode is a conductor through which electric current enters or leaves a medium, such as an electrolyte or a vacuum. It is commonly made of metals or conductive materials and plays a crucial role in various electrical devices, including batteries, electrolysis systems, and sensors. Electrodes come in two types: anode and cathode. The anode is the electrode where oxidation occurs, while the cathode is where reduction takes place. Together, they facilitate chemical reactions that generate electrical energy or enable the flow of current in devices like solar cells and fuel cells.