Final answer:
Erving Goffman referred to 'd. stigma' as the negative label that can transform a person's self-concept and social identity, leading to societal exclusion and possibly contributing to secondary deviance.
Step-by-step explanation:
The concept used by sociologist Erving Goffman to refer to a powerful and negative label that greatly changes a person's self-concept and social identity is d. stigma. Goffman introduced the idea that individuals manage impressions of themselves through a process he likened to actors performing on a stage, with each situation being a distinct performance, which is part of his theory known as dramaturgy. Stigma, particularly in contexts such as health, can have a significant impact on an individual's self-concept and quality of life, often resulting in prejudice, discrimination, and social exclusion, which can hinder a person from fully integrating into society. This stigma can become so pervasive that it defines an individual's master status, or the primary characteristic others use to identify them, and can influence the level and type of healthcare they receive.
In extremely severe cases, being labeled with a stigma can lead to secondary deviance, where a person begins to change their behavior to align with the deviant role ascribed to them, which Erving Goffman and Edwin Lemert have described in their works on the interactions of self-identity with societal labels.