A composition whose entire body — typically ending in a tihai — is itself stated three times, the final stroke of the third statement landing on sam. Since the internal tihai has three landings, a full chakradhar delivers nine, in three waves: the tradition's grandest cadence.
The arithmetic must be exact across multiple avartans, which is why chakradhars are calculated, memorized, and prized. Named subtypes tighten the rules — farmaishi and kamali place specific internal Dhas on sam. In Kathak and solo playing alike, a big chakradhar is the standard summit of a set.
Reference: Sudhir Kumar Saxena, The Art of Tabla Rhythm: Essentials, Tradition and Creativity (D.K. Printworld, 2013).