A syndicate pronounced Syn-di-cate is a self-organizing group of individuals, companies or entities formed to transact some specific business, or to promote a common interest.

In the case of criminal activity, it is there to promote, and engage in, organized crime. The term is also associated with anarchist theory, specifically anarcho-syndicalism, in which it forms an alternative to both the nation state and capitalist corporations.

The word syndicate comes from the French word syndicat which means trade union (syndic meaning administrator), from the Latin word syndicus which in turn comes from the Greek word σύνδικος (syndikos) which means caretaker of an issue, compare to ombudsman or representative.

Crime syndicates are criminal organizations 'running common illegal big businesses'.^{[citation needed]}

In media, syndicates are organizations by name and credit.

In finance, a group of banks lending, for a specific purpose and to one single borrower, a usually large amount of money is referred to as a bank syndicate or often only as a syndicate.

"Jack the Ripper" is the best-known name given to an unidentified serial killer who was active in the largely impoverished areas in and around the Whitechapel district of London in 1888. The name originated in a letter, written by someone claiming to be the murderer, that was disseminated in the media. The letter is widely believed to have been a hoax, and may have been written by a journalist in a deliberate attempt to heighten interest in the story. Other nicknames used for the killer at the time were "The Whitechapel Murderer" and "Leather Apron".

Attacks ascribed to the Ripper typically involved female prostitutes from the slums whose throats were cut prior to abdominal mutilations. The removal of internal organs from at least three of the victims led to proposals that their killer possessed anatomical or surgical knowledge. Rumours that the murders were connected intensified in September and October 1888, and letters from a writer or writers purporting to be the murderer were received by media outlets and Scotland Yard. The "From Hell" letter, received by George Lusk of the Whitechapel Vigilance Committee, included half of a preserved human kidney, supposedly from one of the victims. Mainly because of the extraordinarily brutal character of the murders, and because of media treatment of the events, the public came increasingly to believe in a single serial killer known as "Jack the Ripper".