The Deities in The Legend of Zelda series are the omnipotent powers of the Zelda universe. They're unarguably the most important race in the series, though are not as notable to the series as Hylians are. The Deities, according to the many games, notably The Legend of Zelda: Ocarina of Time, created the world, the laws, and the creatures that would follow the laws. They named the Hylians as the most prominent species and the ones that would fulfil their wishes. The other species would serve the Hylians, and some, notably the Gerudo, would become jealous, though others such as the Sheikah would honor the Deitie's jurisdiction.
Basically there are levels of Deities. The higher and lower ones are separated into their specific category, with the capital gods Din, Nayru, Farore, Hylia, Zephos, and Cyclos being the most notable gods, and others such as the Great Deku Tree, The Four Giants, and others being spirits.