The paper explores the origin and semantic derivation of Latin philosophic term “mōrālitās” (“morality”), keeping in mind its generalizing and object-giving function in modern moral philosophy, which is obvious in its derivates in European languages. The semantic derivation of “mōrālitās” is being examined by means of comparative analysis of lexicographical data in three dictionary groups: that of the Late Latin (when the word “mōrālitās” first occurs), of the Medieval Latin (when it enters philosophical lexicon) and that of Early Modern Latin (when the term became widespread and got its modern meaning). To cover the lack of lexicographical information in the latter two groups of dictionaries the study uses Google Books full-text search, which statistically proves, that the term gained popularity only in the first half of 17th century and also gives important clues on the development of its meaning in late scholasticism. In conclusion, it is stated, that semantic derivation of the term in Late, Medieval and Early Modern Latin shares the same common guidelines, namely steady synonymic ties with emerging substantive forms of the adjective “mōrālis” (moral) and term phrases, formed with “mōrālis” and “mōs” (habit, custom). As a result of such a derivation “mōrālitās” came to be highly polysemic term, denoting the very quality of the free and conscious action, its moral worth and the rules to estimate the worth, and the philosophical discipline for doing that, and the subject of this discipline in the same time.