Equilibrium in a perfectly competitive market can be defined as

Zero excess demand-zero excess supply situation Some excess supply-zero excess demand situation Some excess demand and some excess supply situation Zero excess demand and some excess supply situation

Zero excess demand-zero excess supply situation

If at a price, market supply is greater than market demand, we say that there is an excess supply in the market at that price and if market demand exceeds market supply at a price, it is said that excess demand exists in the market at that price. Therefore, equilibrium in a perfectly competitive market can be defined alternatively as zero excess demand-zero excess supply situation.