A set of formal constraints like those above, expressed in a suitable modal language, can therefore be used to (partially) characterize a conceptualization, in the sense of excluding unintended extensions of the relevant relations even for possible “worlds” different from the one considered. Notice that in general we cannot identify a single conceptualization by means of a set of formal constraints, since such a set may have many models. The set of such models is exactly what in [9] we defined as ontological commitment. According to these considerations, we cannot see a particular theory as a specification of a conceptualization, since conceptualizations can be only partially characterized. What we can specify is a set of conceptualizations, i.e. an ontological commitment. [...] Strictly speaking, none of them can be considered as a specification of a conceptualization, and hence Gruber’s definition cannot apply. If we want to mantain its original (good) intuitions, we must weaken Gruber’s definition, claiming that an ontology is only a partial account of a conceptualization.