Is Ceres a dwarf planet or asteroid?

Answer 1

By the definition of the International Astronomical Union a dwarf planet is an object that:

1. Orbits the sun.
2. Is massive enough to be made round by its own gravity.
3. Has failed to "clear the neighborhood" of debris.

Ceres, the most massive object in the asteroid belt, meets these three criteria. If it had managed to "clear the neighborhood" then it would be considered a planet.

Answer 2

Dwarf Planet (noun)

a spherical celestial body revolving about the sun, similar to a planet but not large enough to gravitationally clear its orbital region of most or all other celestial bodies.

Answer 3

Pluto and Ceres are both considered to be dwarf planets because they are so much smaller than a planetary mass would be. Because of their small size they are classified as dwarf planets.

Answer 4

Ceres is both an asteroid and a dwarf planet.