Question

what do you mean by thermodynamic equilibrium

Answer 1

Thermodynamic equilibrium is an axiomatic concept of thermodynamics. It is an internal state of a single thermodynamic system, or a relation between several thermodynamic systems connected by more or less permeable or impermeable walls.

Answer 2

The equilibrium at which two systems are thermally equilibrium with each other or the equilibrium attained when both the systems are at same thermal conditions and obey the zeroth law. This type of equilibrium is thermodynamic equilibrium