A cloisonné dial is a type of enamel dial that was more prominently offered in the 1950s, though in small number, and involves the partitioning of the dial using silver or gold wire to create a design. The spaces are then filled with enamel (a soft glass, to which different elements are added to create color), and then fired these dials at between 800-1200 degrees Celsius. In repeated firing, the enamel then melts and bonds to the metal dial.
Read on Perpetuelle for a description of Enamel Explained: The Art of Cloisonné, Grand Feu, Champlevé, Paillonné, Flinqué & Other Enamel Techniques.