This article is devoted to the number and variety of dictionaries, glossaries and encyclopedias of literary, stylistic and poetic terms which have been increased nowadays. It also becomes clear that terminology is a specific branch of lexicology –specific one, because it is concerned with the conventional semiotic system and not ordinary language as spontaneously arising out of the needs of natural human communication. New concepts have spread over the world and become familiar with many terms that name them. Not only the scientists are interested in studying the terms and terminology but the students, teachers, theorists of translation, too. We will stress the main factors which generated this type of infiltration in order to define the notions of term and terminology. The concepts constituting the theory are not original, but as it is in other interdisciplinary subjects, they are borrowed from the neighboring disciplines, in this case linguistics, logics, ontology, philosophy, etc. If we accept that terms constitute a subcomponent of the lexicon of the language, since a speaker’s competence cannot exclude a specialized vocabulary, the terminology clearly forms a part of linguistics.