Nobility titles in the United Kingdom are ranks of honor and status that have been historically associated with the aristocracy. The main titles include Duke, Marquess, Earl, Viscount, and Baron. These titles can be hereditary, passed down through generations, or granted by the monarch for various services to the crown. Each title comes with specific privileges and responsibilities, often linked to land ownership and governance. The Peerage system governs these titles, and members of the nobility may sit in the House of Lords, contributing to the legislative process.