Ceres is neither an inner nor an outer planet. It is a dwarf planet located in the asteroid belt between Mars and Jupiter.

Here's why:

* Inner planets are the four rocky planets closest to the Sun: Mercury, Venus, Earth, and Mars.

* Outer planets are the four gas giants further out: Jupiter, Saturn, Uranus, and Neptune.

* Dwarf planets are celestial bodies that orbit the Sun, are massive enough to be rounded by their own gravity, but have not cleared their neighborhood of other objects.

Ceres fits the definition of a dwarf planet but doesn't fit the definition of either an inner or outer planet.