clique: used to describe a group of persons who interact with each other more regularly and intensely than others in the same setting. Cliques are distinguished from “crowds” in that their members interact with one another

crowds: large groups of adolescents defined by their shared image and reputation

homophily: a tendency of individuals to form links disproportionately with others like themselves

deviant peer contagion: the process by which peers reinforce problem behavior by laughing or showing other signs of approval that then increase the likelihood of future problem behavior

peer pressure: encouragement to conform to one’s friends or contemporaries in behavior, dress, and attitude; usually considered a negative force, as when adolescent peers encourage one another to defy adult authority