Abstract
<jats:p>The research aims to characterize the semantic processes within the medical sublanguage from a diachronic perspective, which allows for tracing the stages of formation and transformation of lexical unit meanings. The article investigates the cognitive-discursive nature of the medical term, analyzes the dynamics of semantic changes in words, and defines the functions of medical terminology. The scientific novelty of the study lies in the fact that, for the first time, the semantic processes of terminologization, determinologization, and transterminologization are examined through a diachronic lens. The analysis is based on data from general-purpose and specialized dictionaries, as well as resources from the Russian National Corpus (RNC). By comparing various dictionaries, it was established that the process of terminologization can be traced in lexicographical sources as early as the beginning of the 20th century and manifests through the development of polysemy and homonymy. The study reveals that the formation of the medical terminological system is characterized by the semantic transition of terms from one professional field to another (transterminologization) and the loss of specialized meanings (determinologization).</jats:p>