Word knowledge can be updated not only by the acquisition of novel words, but also by the learning of new meanings for words with established meanings. We are interested in determining the interaction between the original and the new meanings. Compared to learning novel word forms, it was previously proposed that memory for new meanings could be initially boosted during acquisition whereas an interference pattern between old and new meanings may appear later during consolidation (Fang et al., 2018). In the present study, native Spanish speakers (18-35 years old) learned novel meanings for 20 words of intermediate frequency (e.g., ‘Scarf’: A bird that doesn`t sing), and 48 hours later they performed a memory test. The study was performed online. Our results showed that while no advantage of familiarity was obtained regarding long-term memory retention of new meanings, a significant increase in learning efficiency was found compared to novel words. Thus, learning new meanings for old words takes significantly less time compared to learning novel words. Ongoing studies are analyzing the perturbation of the original meaning using a semantic decision task. The next step will analyze the role of a reactivation stage before the learning task. The central hypothesis is that the process of reactivating the memory of words would be a fundamental tool for updating definitions, allowing greater integration and less interference between the different meanings.