The standard translation for the Syriac word myatrūṯā is believed to be virtue (ἀρετή). The present article demonstrates that this is not so evident. The etymological analysis shows that the semantics of the stem YTR is constructed around the idea of tension (nervous or muscular). Syriac lexicographers registered some further developments, as the derivatives acquired meanings of abundance, benefit and convenience. The most sophisticated is the latest meaning of dignity out of which moral excellence has been extracted. Syro-Arabic lexicographers prefer to use words constructed upon the root fḍl thus reflecting the semantic shift. Greek word initially connected with military bravery has been chosen for the translation of myatrūṯā because of that later development. In the Syriac mystical literary Corpus the word myatrūṯā continued to be used in different ways. For the analysis Memre 1-6 fron the First Collection of Isaac have been chosen. Greek translators of St Isasac of Nineveh Patrikios and Abraamios inevitably used ἀρετή to render myatrūṯā. In the article a tentative semantical formalization for the word myatrūṯā has been performed. It falls into four vectors: ascetics in general (a); spiritual life (b); abundance (c) and, finally, acquired habit of good-doing (= virtue) (d). The results are preliminary but a somewhat more nuanced approach to the translation and understanding of the word in question seems to be a must.