Labeling is describing someone or something in a word or short phrase. It has been argued that labeling is necessary for communication. However, the use of the term labeling is often intended to highlight the fact that the label is a description applied from the outside, rather than something intrinsic to the labeled thing.
Labeling theory focuses on the linguistic tendency of majorities to negatively label minorities or those seen as deviant from norms. The theory is concerned with how the self-identity and behavior of individuals may be determined or influenced by the terms used to describe or classify them, and is associated with the concept of a self-fulfilling prophecy and stereotyping.
Herbert Mead posited that the self is socially constructed and reconstructed through the interactions which each person has with the community. Each individual is aware of how they are judged by others because he or she has attempted many different roles and functions in social interactions and has been able to gauge the reactions of those present. This theoretically builds a subjective conception of the self, but as others intrude into the reality of that individual's life, this represents objective data which may require a re-evaluation of that conception depending on the authoritativeness of the others' judgment.
If deviance is a failure to conform to the rules observed by most of the group, the reaction of the group is to label the person as having offend against their social or moral norms of behavior. This is the power of the group: to designate breaches of their rules as deviant and to treat the person differently depending on the seriousness of the breach. The more differential the treatment, the more the individual's self-image is affected.