Lexicography is one of the oldest linguistic sub-disciplines and began to compile extensive corpora early on as the basis for dictionary work. Surprisingly, these corpora and the dictionary articles have not been used very frequently for the study of language variation, although most dictionaries do not only contain information about word meanings and grammar, but also on regional distribution or style level. This volume explores the value of lexicographical data in the study of language variation. The contributions focus on different types of dictionaries for different languages as well as on various linguistic research questions ranging from the dictionaries'' approach to loan words or morphology to practical issues regarding digital frameworks for lexicographic work.