Supply curve

Supply curve is the graphed relationship between quantity (on the x-axis) and price (on the y-axis) for suppliers of a good or service. In other words, the supply curve illustrates the amount of something that a supplier is willing to produce if he can sell it at a certain price. This curve is usually upward-sloping (i.e., has a positive slope), because a supplier is willing to produce more of something the higher the price he can sell it at.

Under assumptions of perfect competition, the supply curve is the part of the marginal cost curve above its intersection at minimum average variable cost. This represents the 'price equals marginal cost' condition.