Acquisition of superordinate classification has traditionally been explained in terms of development of class inclusion. More recently, alternative explanations have been put forward by many authors, who consider superordination, as a product of linguistic and metalinguistic acquisitions. An experiment was carried out aimed at understanding the role of metalinguistic knowledge—defined in terms of the nominal realism/nominal relativism distinction. Subjects were 41 children from 7 years 1 month to 8 years 9 months, presented with a free-definition task of objects belonging to familiar categories and a questionnaire regarding the origin of names, their nature, exchangeability, etc. A significant correlation was found between spontaneous definitions of objects and conceptions of the relationships between names and things: Those subjects who are aware of the historical and cultural origin of names (decline of ontological realism) are also able to use superordinates in their definitions. However, superordination is not linked to awareness of the arbitrary nature of the word-referent connection (decline of logical realism).