What is the meaning of equilibrium in mechanics and equilibrium in thermodynamics?

(N/A) Equilibrium in mechanics means that the net external force and the net external torque acting on a system are zero.
Equilibrium in thermodynamics means that the macroscopic variables (such as pressure,volume,temperature,and composition) that characterize the system do not change with time.
Whether or not a system is in a state of equilibrium depends on the surroundings and the nature of the wall that separates the system from the surroundings.
For example,a gas inside a closed rigid container,completely insulated from its surroundings,with fixed values of pressure,volume,temperature,mass,and composition that do not change with time,is in a state of thermodynamic equilibrium.