In the paper, a new approach to the notion of visualization metaphor is suggested based on semiotic analysis. The structure of the metaphor and the notion of visualization language are considered. Critical analysis is performed on how the notion of metaphor has been used in the theory of computer–human interface (CHI) and in the modern practice of interactive and visual environment design. Prototype tools for formal and empirical quality evaluation of visualization metaphors and languages based on the notion of adequacy in visualization are described.