Black Market

No matter where it occurs throughout history or across any number of civilizations, the concept of a black market remains the same: it is an underground economy, usually working against or in violation of a given set of laws or standards. If a product or service is p rohibited from being produced or distributed, then taking part in the production, consumption, or utilization of the illicit commodity is considered a black market trade. It differs from the white market, wherein trade is legally sanctioned, and the gray market, wherein trade is legal, but the manner in which it is carried out is unofficial or otherwise unsanctioned. Because the legality of a good or service can vary from place to place and culture to culture, what is part of the black market in one location may not be part of the black market in another location.
Perfect examples of this in the United States are drugs and prostitution. In a growing number of states, recreational marijuana use is legal; in those locations, recreational use of the drug is no longer considered part of the black market, though it would be in a neighboring state where the drug is still considered illegal. Similarly, prostitution is illegal in the United States; certain parts of Nevada, however, have legalized the sex trade under a watchful government eye. In these areas, prostitution is no longer part of the black market; individuals soliciting prostitutes in other parts of the state and country, though, are said to be engaging in a black market transaction.