Although there are currently only four designated dwarf planets, there are at least 41 known objects which may qualify when we get around to it. And when the Kuiper belt is fully-explored, there may turn out to be another 200. Beyond that there may be another 2000 subplanets in our solar system.
Ceres is named after the Roman goddess of cereals (as in grasses cultivated for their edible parts and not as in the milky bowls of breakfast candy eaten by toddlers and people living in dorms), abundance, and motherly love. She was both the sister and wife of Jupiter. Her worship was adopted by the Romans in 496 BCE, during a particularly severe famine. Her followers were mostly plebes who controlled the grain game in antiquity. For some reason, their rites included tying burning sticks to fox's tails.
The original name for the planetoid was Ceres Ferdinandea but that got shot down as not everyone was so keen on brown-nosing Spanish royalty. The dwarf planet is the smallest of the currently designated subplanets. It was actually discovered way back in 1801 by Giuseppie Piazzi who wrote, "since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet." Even further back, Johann Elert Bode, in 1768, had suggested that there may be a planet between Mars and Earth. And lo, Ceres is situated within the asteroid belt.