Thermodynamic equilibrium is a state in which a system's macroscopic properties, such as temperature, pressure, and volume, remain constant over time. In this state, there are no net flows of energy or matter within the system or between the system and its surroundings. This means that all parts of the system are uniform and balanced, leading to stability. When a system is in thermodynamic equilibrium, it is also in a state of maximum entropy, meaning that energy is distributed evenly. This concept is crucial in understanding processes in thermodynamics, as it helps predict how systems will behave under various conditions, such as in engines or refrigerators.