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Thermal equilibrium is the state of a thermodynamic system (e.g., a gas cloud) such that there is no net heat flow, e.g., everything in it being the same temperature. It is a key internal characteristic of a black body, i.e., the condition that produces black-body radiation. Real-world matter can be quite close to thermal equilibrium, but actual thermal equilibrium is a theoretical state, useful in modeling situations where heat flow is minimal.
Thermodynamic equilibrium is thermal equilibrium plus equilibrium of additional aspects: chemical equilibrium, mechanical equilibrium, and radiative equilibrium.