- state where opposing forces, flows, or rates balance, producing no net change
- static equilibrium: object at rest with zero net force and zero net torque
- dynamic equilibrium: forward and reverse processes occur at equal rates (e.g., chemical reactions)
- chemical equilibrium described by the equilibrium constant K and Le Chatelier’s principle
- thermodynamic equilibrium: uniform temperature, pressure, and chemical potential throughout
- Nash equilibrium in game theory: each player’s strategy is optimal given others’ strategies
- ecological equilibrium: population sizes stabilize through feedback loop mechanisms
- market equilibrium: supply equals demand at a specific price
- systems displaced from equilibrium tend to return (stable) or diverge (unstable)