Gang is a group of persons who go about together or act in concert, especially for especially for criminal or illegal purposes. They are a group of people sharing a common identity. Many gangs have common identifying signs and symbols. Gangs are also termed as street gangs.
Example of a State Statute ( Illinois) defining Gang
According to 740 ILCS 147/10 "Streetgang" or "gang" or "organized gang" or "criminal street gang" means any combination, confederation, alliance, network, conspiracy, understanding, or other similar conjoining, in law or in fact, of 3 or more persons with an established hierarchy that, through its membership or through the agency of any member engages in a course or pattern of criminal activity.