Definition: The price at which the number of units produced equals the number of units sold, supply and demand also take a part in this balance. Equilibrium price is where the supply and demand curves intersect. (Investopedia)

Example # 1  This graph show two different equilibrium prices, P&Q and P1&Q1 show that at that a certain price and a certain quantity is demanded producing equilibrium.

Example 2: This cartoon shows that when supply and demand are equal the market is balanced.