Formal variation of the terms describing human infectious diseases (based on the material of the English language)

The aim of the research is to construct a typology of formal variants of terminological units describing human infectious diseases. The author analyses the similarities and differences between the phenomena of synonymy and variation, presenting two opposite views on the attitude of linguists toward this problem. Then the phenomenon of formal variation is considered separately from synonymy. The scientific novelty of the research lies in a comprehensive approach to studying formal variant terms and constructing their typology. As a result of the study, the main reason for the variation of professional units of infectiology has been determined, i.e., the active process of borrowing of special vocabulary in English under the influence of Greek-Latin bases. The typology of variation of terms is represented by graphic, word-formation, syntactic, morphological-syntactic and phonetic variants. A separate group of formal variants is identified, including lexically related terms, where the replacement of word combination components is the result of semantic clarification, conceptual expansion or replacement of borrowed words. The preservation of functionality of the identified variants of terms in modern scientific literature has been established.