The Duden is a comprehensive dictionary of the German language, first published in 1880. It serves as an authoritative reference for spelling, grammar, and usage, helping users understand the correct forms of words and their meanings. The dictionary is regularly updated to reflect changes in the language and includes various editions tailored for different audiences. In addition to the main dictionary, the Duden series includes specialized volumes on topics like synonyms, style guides, and grammar rules. It is widely used in schools, universities, and by professionals, making it an essential resource for anyone studying or using the German language.