Thermoelectric effect refers to a circuit composed of two conductors, known as a "thermocouple." These conductors are called "thermoelectrodes," and the resulting electromotive force is known as "thermoelectric potential."

When two different conductors or semiconductors, A and B, form a circuit and their ends are interconnected, an electromotive force (EMF) is generated in the circuit as long as the temperatures at the two nodes are different. One end, with temperature T, is referred to as the working end or hot end, while the other end, with temperature T0, is called the free end (also known as the reference end) or cold end.