Concepts are so fundamental to human cognition that Fodor declared the heart of a cognitive science to be its theory of concepts. To study concepts, though, cognitive scientists need to be able to identify some. The prevailing assumption has been that they are revealed by words such as triangle, table, and robin. But languages vary dramatically in how they carve up the world with names. Either ordinary concepts must be heavily language dependent, or names cannot be a direct route to concepts. We asked speakers of English, Dutch, Spanish, and Japanese to name a set of 36 video clips of human locomotion and to judge the similarities among them. We investigated what name inventories, name extensions, scaling solutions on name similarity, and scaling solutions on nonlinguistic similarity from the groups, individually and together, suggest about the underlying concepts. Aggregated naming data and similarity solutions converged on results distinct from individual languages.