The problem of rendering of some philosophical terms is discussed in this article. Reproduction of key metaphysical terms plays significant role in general structure of translated philosophical text. The division of being into ens reale and ens rationis is one of the most important keys for understanding of St.Thomas' philosophy. The gradual transformation of previous philosophical traditions into ideas of St. Thomas' teaching is apparent on the material of certain metaphysical terms. In their own turn, Thomistic ideas develop into subsequent philosophical streams. The medieval discussion on relations has started in Boetiu's translation and commentaries on Aristotle's "Categories". The notion of relation was subsequently developed by St. Thomas in his "Summa Theologiae" and defined by John Poinsot in his "Tractatus de Signis". This article, as a part of solid interdisciplinary research on scholastic terminology, is based on Ukrainian translation of "Summa Theologiae". The meaning and rendering options of term "relation" is researched in this work. Terminology is the most essential feature in every philosophical text, hence it must be clear and understandable, especially the terminology of St. Thomas' works. The problem is Ukrainian philosophical terminology is not established yet. It is still on the stage of formation. In fact, there are only two ways of rendering from Latin into Ukrainian: the first method to be used is transliteration, i.e. rewriting the word according to the rules of the target language, the second one is copying, i.e. reproduction of morphological structure of a word. The difference between these methods presupposes discrepancy in semantic content of a term. At the first glimpse, transliteration seems to be more convenient, but it is not really so. In such case the translator would get a strange text full of incomprehensible words. It is much easier to translate all the terms by transliteration. But completely different approach to rendering philosophical terms is based on copying. This method consists in precise translation of morphological structure of a word. Prefix, root, suffix and ending are rendered separately by equivalents of the target language. A striking example of this approach is the term "relatio" and its rendering into Ukrainian that is discussed in the article.
