This contribution treats the concept of a specialised translation dictionary and argues that this concept is much broader than the traditional vision of a bilingual dictionary going from source language to target language. Based on a methodology developed in the framework of the function theory and using qualitative evidence from existing user research, the contribution then discusses the respective phases and sub-phases of the overall translation process where lexicographically relevant problems and needs may occur. Subsequently, it discusses how these needs could be solved in a complex combination of monolingual and bilingual lexicographical solutions and presents an overall concept of a specialised translation dictionary together with some general principles. Finally, it provides examples of how these principles can be applied in both printed and online dictionaries using already available techniques from information and computer science.