There are actually five characteristics that define a dwarf planet, not three. Here they are:

1. Orbits the Sun: It must be in orbit around the Sun, not a star or another planet.

2. Has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape: This means it's round or nearly round due to its own gravity.

3. Has not cleared the neighborhood around its orbit: This means it shares its orbital space with other objects of comparable size.

4. Is not a satellite: It must not be a moon orbiting another planet.

5. Is not a star: It's a planet, not a star.

Let me know if you have any other questions about dwarf planets!