Based on a new understanding of the term, the monograph develops a theory of terminology that covers the main questions of this section of knowledge: what is the term? what are the limits of term variation? what role do various aspects of its motivation and the degree of its motivation play in the formation of a particular terminology? what is the conceptual organization of terminology? what is the relationship of the term with other types of special vocabulary of a scientific and technical nature and, in particular, with professional vocabulary and nomenclature?