"Dictionnaire de la langue verte" is a dictionary of slang or "green language", which became a classic source for the study of French slang of the 19th century. The author, Alfred Delvaux, has devoted many years to researching and documenting the slang vocabulary and expressions used by various social classes during this period. In this book, the reader will find a variety of expressions that describe the life and language of the world of underground culture and exalt the uniqueness and colorfulness of the "green language". "Dictionary of the green language" is not only a reference book, but also a window into the history and contradictions of social relations in France in the past centuries.