A Coordinator is a Pokémon Trainer who trains their Pokémon to show off its own beauty, then enters their Pokémon in Pokémon Contests.
In the anime, every Coordinator has one goal, to receive the coveted Ribbon Cup to become a Top Coordinator. To accomplish this, they must win at least five Ribbons of a certain region, for example Sinnoh, so they can enter the Grand Festival.