["Topics in Cognitive Science, EarlyView. ", "\nAbstract\nKin terms appear among infants’ earliest words, yet a full mastery of kin concepts typically emerges only in late childhood. This prolonged developmental trajectory reflects not only children's acquisition of an abstract relational system of words, but also their growing understanding of social relationships and interactional norms. In this paper, we review research on kin term acquisition from three perspectives: word learning, language socialization, and social learning. We then outline the problem space for a contemporary study of kin term acquisition, highlighting the most urgent barriers to understanding the nature of kin representations and their development. We close by introducing findings from two pilot studies that shed light on how social, cultural, and linguistic experience shapes kin term acquisition. By bringing together insights from psycholinguistics, linguistic anthropology, and infant social cognition, we aim to capture the richness of kin concepts in development and to offer a framework that can inspire future research across these fields."]