Redox, short for reduction-oxidation, refers to a type of chemical reaction where the oxidation state of one or more substances changes. In these reactions, one substance loses electrons (oxidation) while another gains electrons (reduction). This transfer of electrons is essential in various processes, including energy production in cells and the corrosion of metals. In a redox reaction, the substance that donates electrons is called the reducing agent, while the one that accepts electrons is known as the oxidizing agent. These reactions are fundamental in many fields, including biochemistry, industrial chemistry, and even in everyday occurrences like rust formation on iron.