What is excess demand?
When the demand for a product exceeds the supply so, there is a shortage of the product in the market (the price is too low)
What is excess supply?
When the supply of a product exceeds the demand so, there is a surplus of the product in the market (the price is too high)
What is an equilibrium price?
When the supply and the demand of the product are in equilibrium. At this price all products are sold.