This chapter discusses major developments in the field of Interactional Semantics. After locating Interactional Semantics within the study of semantics and introducing major contributions to the field, two approaches for studying semantics in interaction are exemplified: The study of meta-semantic practices (in particular, defining) is concerned with actions by which participants clarify local meanings of expressions they are using; the study of interactional histories is concerned with how the accumulation of common ground over a series of interactions affects both lexical choices and the interpretation of the expressions used. The studies show how indexicality, action-orientation, and recipient-design are basic properties of semantic practice in social interaction.