This study focuses on Fakhr al-Dīn al-Rāzī’s thesis of the impossibility of giving a complete definition (al-ḥadd al-tāmm) and discusses its impact, the parties to the debate, and especially the positive argument contra al-Rāzī by the Ottoman savant Ṭāşköprīzāde. The negative argument of al-Rāzī postulates that the complete definition is strictly circular, for the totality of parts that makes up the defined object are included in the definition, and the object is identical to the sum of its parts. Therefore, complete definition strictly commits the fallacy of definining a thing by itself. Ṭāşköprīzāde argues against this view by defending the possibility of complete definition. According to him, although in complete definition the defined object and the defining features include the same set of things, the modes of their presentation to the mind are different. Thus, a complete definition becomes circular only if both the content of the defined object and its mode of presentation to the mind are the same. If it can be shown that the contents of the definiendum and definiens have distinct modes of presentation, then the charge of circularity is discarded. In this article, I illustrate the two opposing approaches by distinguishing between form and content, or sense and reference. Both parties take for granted that the contents of the definiens and the definiendum are the same when it comes to the complete definition. The main point of contention lies in the modes of apprehending the contents. This article analyzes the arguments of two opposing semantic theories particular to the complete definition and shows that the question emerges as a result of the theories of constant form and variable form concerning meaning. In the period between al-Rāzī and Ṭāşköprīzāde, Ṭūsī bolstered the complete definition whereas al-Ījī refuted it. Both Ṭūsī’s and al-Ījī’s arguments will be discussed, though briefly, in the body of paper as well.