Equilibrium is a state of balance or rest, lacking in any tendency to change. In economics, the equilibrium price is the price at which demand equals supply, and there is neither a surplus nor shortage of goods.
Types of equilibrium:
A system in equilibrium does not necessarily have to be static. A chemical reaction, for example, is considered to be in dynamic equilibrium when the forward and backward rates are equal. This means that, while reactants are converting to products and vice versa, the system is still at equilibrium because the overall concentration of each component is constant over time.