A gang is a group or society of associates, friends or members of a family with a defined leadership and internal organization that identifies with or claims control over territory in a community and engages, either individually or collectively, in illegal, and possibly violent, behavior. Gangs arose in America by the middle of the nineteenth century and were a concern for city leaders from the time they appeared. Some members of criminal gangs are "jumped in", or have to prove their loyalty and right to belong by committing certain acts, usually theft or violence.
