Naming refers to encountering a new word and subsequently being able to use it both expressively and receptively. Sometimes, this can happen in as little as a single experience. Several recent studies have explored factors that influence the acquisition of naming in adults. However, these studies used familiar stimuli for which the participants already had names. In these studies, preexisting stimulus-response relations with the stimuli could have impeded the acquisition of new names for some participants. In contrast, the present study used unfamiliar ("arbitrary") stimuli. In addition, an equivalence test was used to validate the findings because some theorists have claimed that naming is required for equivalence. The results revealed some advantages to teaching naming with arbitrary stimuli. Interestingly, a subset of participants had high scores on equivalence tests without having high scores on expressive tests. This indicates that, contrary to naming theory, naming may not be necessary for equivalence and match-to-sample tests may not be the best test of equivalence. These findings support the independence of the expressive and receptive repertoires both in the development of naming and equivalence.