<p>Social interaction is argued to play a crucial role for grounding abstract knowledge, yet empirical evidence is scarce. To investigate whether social interaction affects the processing of abstract words, 60 French speakers semantically categorized the degree of socialness and concreteness of words either individually or in dyads. When judging the socialness of words, dyads showed a processing advantage for abstract social words that was absent in individual performance. In contrast, when judging the concreteness of words, dyads were less accurate for abstract social words than individuals, confirming that social interaction renders these words more concrete. Dividing the dyads by their level of social engagement based on gaze patterns revealed that the effects were driven by the more cooperative dyads. The findings demonstrate that language processing is distinct between interactive and isolated contexts, where social interaction and engagement dynamically shape the interpretation of abstract concepts.</p>