Radharani Radha (meaning “the highest pinnacle of worship”) is her name. Rani (queen) is her position. And Krishna is her eternal lover.
The Gaudiya Vaishnava spiritual tradition which is the predominant form of worship practiced in Vraja, describes God as both male and female. God is both Radha and Krishna. The ancient treatise, Caitanya-caritamrita, (Adi-lila, 4.55-56) explains that they are one, but Krishna expands into two, himself and Radharani, for the sake of divine loving pastimes. If they remained as one, then there would be no relationship, no pastimes, and there would be no dynamic exchange of love.
Sri Krishna enchants the world with his beauty and charm, and Sri Radha enchants him. Therefore she is the Supreme Goddess. Sri Radha is the full power and Krishna is the possessor of full power. (Cc.Adi-lila, 4.82, 84, 87-96) Thus, the two are non-different, as the sunshine is non-different from the sun, or as the energy is non-different from the energetic or source of energy.