A person, usually a woman, who is paid money to have sex with the customer. Don't patronize the ones in Tijuana, they invariably try to negotiate a better rate in the middle of the session, refusing to continue till you pay more. This is a lot like the Teamsters and other unions affiliated with organized crime. In Thailand and the Philippines it is common for prostitutes to actually be men who have had sex change operations. State of the Art is so good, you often can't tell.