At present, a growing number of linguists are actively exploring terminology in a variety of ways: linguo-culturological, linguo-cognitive, semantics, pragmatic and others. The relevance of this study is determined by the need for an in-depth analysis of terms used in professional communication between specialists in various fields. Therefore, it seems relevant to study lexical units in bilingual Tatar-Russian and Russian-Tatar dictionaries of the XIX century. The article deals with lexical units that function in bilingual dictionaries of the XIX century and are part of the terminological field of medical vocabulary. The material of the study is lexical units, selected from Tatar-Russian and Russian-Tatar dictionaries of the XIX century. The scientific novelty of the study is evident against the backdrop of the lack of works on the study of the semantics of medical vocabulary, which were used in bilingual dictionaries of the ХIХ century. Bilingual dictionaries of the XIX century were analyzed, and conclusions were drawn about the presence of medical vocabulary.