An isothermal process is a thermodynamic process that occurs at a constant temperature. During this process, the system exchanges heat with its surroundings to maintain the same temperature, even as it undergoes changes in pressure and volume. This is commonly observed in ideal gases, where the internal energy remains constant. In an isothermal process, the relationship between pressure and volume is described by Boyle's Law, which states that the product of pressure and volume remains constant for a given amount of gas at a constant temperature. This principle is essential in understanding various applications, such as in heat engines and refrigeration systems.