Second-degree price discrimination
A form of price discrimination in which different units of a product are sold at different prices. A discount for buying in bulk is an example of second-degree price discrimination. Another form of second-degree price discrimination is commodity-bundling. Two products (such as a computer and the operating system) can be sold separately or as a bundle. Selling the bundle for less than the sum of prices of the two products is second-degree price discrimination. The benefit of bundling for the seller is that it may attract additional consumers who would not have purchased the separate products. See also first-degree price discrimination; third-degree price discrimination.
Reference: Oxford Press Dictonary of Economics, 5th edt.