In the light of foreign language vocabulary use increase in Russian language at the end of XX-th - the beginning of XXI-st century due to the intensification of business, scientific and cultural ties between the countries the study of foreign language terminology borrowing becomes increasingly important. Usually, a borrowed term retains the meaning of a term prototype in an accepting language or is exposed to terminologization, transterminologization or terminological derivation. These mechanisms are closely related to the general processes of borrowing semantic transformation, such as narrowing or widening of a prototype word semantic scope. This article demonstrates the analysis of the semantic transformations concerning the borrowed scientific and technical terms of French origin, included in Russian language during the XIX-XX-th centuries. The study is carried out within the basic methods of linguistic analysis such as descriptive methods, comparative method and component analysis. During the analysis of the test body concerning the borrowed scientific and technical terms of French origin (228 units) it was found that in the course of borrowing term semantics formation in the system of an accepting language the preservation of a prototype term meaning (30% of terms) takes place as a rule, often exposing its meaning to specification or terminologization (20% of terms). The rest of borrowed terms are subjected to the semantic scope expansion on the basis of secondary borrowing mechanisms or the development of new meanings on the basis of Russian language. This allows to use them in other fields of terminology and leads to the appearance of cross-field homonyms. Thus, the transformation of a borrowed term semantics includes it in term formation processes and in Russian language system in general. The analysis of the semantic adaptation stage concerning scientific and technical terms is of particular importance in terms of their lexicographical description and it also allows to identify national and international element in Russian language within the light of scientific terminology increasing internationalization
