Absolute monopoly

What does Absolute monopoly mean in American Law?

The definition of Absolute monopoly in the law of the United States, as defined by the lexicographer Arthur Leff in his legal dictionary is:

A species of monopoly in which one firm controls the entire output of a service or commodity for which there is no substitute. This is an exceedingly rare situation in any real economic world of any complexity and development. It may be best to consider absolute monopoly, like most absolutes, as a theoretical construct, the limit toward which all monopolization tends but cannot reach. See also oligopoly.