Prostitution is the act or practice of providing sexual services to another person in return for payment
A payment is the transfer of wealth from one party to another. A payment is usually made in exchange for the provision of goods, services or both, or to fulfill a legal obligation....

. The person who receives payment for sexual services is called a prostitute and the person who receives such services is known by a multitude of terms, including a "john". Prostitution is one of the branches of the sex industry
Sex industry
The sex industry consists of businesses which either directly or indirectly provide sex-related products and services or adult entertainment...

. The legal status of prostitution
Prostitution and the law
The laws of prostitution vary widely from country to country, and between jurisdictions within a country. Prostitution is legal in some parts of the world and regarded as a profession, while in other parts it is a crime punishable by death. In some jurisdictions prostitution is illegal...

 varies from country to country
Prostitution by country
The laws on prostitution vary considerably around the world. In some jurisdictions prostitution is illegal. In other places prostitution itself is legal, but most surrounding activities are illegal, often making it very difficult to engage in prostitution without breaking any law...

, from being a punishable crime to a regulated profession. Estimates place the annual revenue generated from the global prostitution industry to be over $100 billion.