We are often told that the meaning of a definiendum of an adequate definition is identical to the meaning of its definiens. This claim appears in Frege’s theory of definitions, and so it appears in Russell’s theory. However, it is worthwhile to remember both philosophers were advocates of the extensional semantics. Yet, the claim is often accepted beyond the realm of extensional theories. Admittedly, the claim is sus- tainable in the intensional semantics. However, as I will argue, it is untenable in the theory of definitions based on hyperintensional semantics.