A reference work devoted to the regional French of Haute-Bretagne, this dictionary records local words, expressions, pronunciations, and usages associated with the area traditionally known as Upper Brittany. It serves readers interested in linguistic variation, regional identity, and the everyday vocabulary that distinguishes French as spoken in this part of western France. The work functions as both a glossary and a cultural record, documenting terms that may appear in speech, oral tradition, or local usage but are often absent from standard dictionaries. Its focus on Haute-Bretagne makes it especially useful for researchers of French dialects, regionalism, folklore, and sociolinguistics, as well as for readers with a personal or scholarly interest in Breton and Gallo-influenced speech communities. Published in a compact hardcover format, it offers a focused guide to the vocabulary of a defined geographic and cultural region, helping preserve and clarify forms of French shaped by local history and community practice.