The IAU Joint Discussion 16 was held at the IAU XXVI General Assembly in Prague, in August 2006. The title of the meeting was Nomenclature, Precession and new models in Fundamental Astronomy. Applications and scientific contribution to astronomy. It was organized by IAU Division I (Fundamental Astronomy) and Commission 19 (Earth Rotation), with the participation of IAU Division, X (Radio Astronomy) and all the Division, I Commissions, as well as with the support of the International Association of Geodesy (IAG). The Scientific Organizing Committee was made up of the three organizers and the representatives of these scientific bodies.