This chapter makes a start in developing the language of description. This enables to address the questions that have set out to address. Through close analysis of sign-making, the aim to develop the social semiotic lexicon people think is needed to produce descriptions and explanatory accounts of all multimodal configurations and interactions. This chapter demonstrates how notions can be used to explore multimodal sign-making by considering three examples from distinct sites and genres: a job interview in a major company in the UK, a status update on Facebook and a surgical operation in a London hospital. Working through these and with occasional reference to some other examples, one introduces the notions of mode, sign, sign complex, resource, affordance, communication and multimodal ensemble. It also focuses on communication, as the semiotic basis on which such an account will rest, and so people make only occasional reference to learning.