Hyperion Syllabification: (Hy·pe·ri·on)Pronunciation: /hīˈpi(ə)rēən/ AstronomyDefinition of Hyperion a satellite of Saturn, the sixteenth closest to the planet, discovered in 1848. It has an irregular shape, with a diameter of 159 miles (255 km). Origin:named after a Titan of Greek mythologyHyperion in other Oxford dictionaries Definition of Hyperion in the British & World English dictionary