Observation, research, experimentation, and verification are the foundational processes giving rise to principles. Principles imply fundamental truths upon which rest knowledge, learning, and teaching. Knowledge and principles are memorialized by and disseminated through words. The denotative word meanings must be agreed upon in order that principles and knowledge can be formally written and spoken. In this way, the structure of scientific information can be built. Three significant psychological terms failing to meet these criteria are self-image, self-concept, and self-identity. Their significance comes from being foundational stones in the structure of one's self-esteem. To illustrate some of the confusion related to them, randomly selected definitions from the psychological literature are presented for the sake of comparison. The purpose of this paper is to attempt to reach a better understanding of these three terms. What will not be discussed here are any literature theories, like Erikson's eight identity stages or Cooley's social interaction "Looking-glass self."