The present paper addresses the categorial content of affixes forming a set of denominal adjectives in Italian, arguing that they are substantially the derivational counterpart of oblique case/adpositions. Specifically, we argue that they act as elementary relators, following Manzini and Franco, who characterized oblique cases and prepositions as general relators expressing the relations is-included (⊆)/includes (⊇), or, in other words, their content is what Belvin and den Dikken dubbed “zonal inclusion”.