Economic Rent
Economic rent is the difference in the amount of money that an individual would be willing to work for, and the amount that they are actually paid. Consider a rock star, or a sports figure who earns, say, a million dollars each year, but would actually be willing to work for $100,000/year. Economic rent, then, equals $900,000 which is a payment provided to the individual (or any type of input) due to their "uniqueness". Another way of thinking about this concept is that an increase in wages will not increase the quantity of labor supplied because the equilibrium wage (which ultimately determines economic rent) is primarily a function of DEMAND for an individual input since supply is relatively fixed.
