In Norse mythology Mundilfari or Mundilfäri (Old Norse, possibly "the one moving according to particular times") is the father of Sól, goddess associated with the Sun, and Máni, associated with the Moon. Mundilfari is attested in the Poetic Edda poem Vafþrúðnismál stanza 23, and in chapter 11 of the Prose Edda book Gylfaginning.
The name appears in various forms in attestations for the figure, some of them significantly different, and various theories have been proposed for the name.John Lindow states that if the first element, mundil- is related to mund, meaning "period of time," then the name may be a kenning for the Moon, as Rudolf Simek theorizes.
Mundilfari (/ˈmʊndᵻlˈvɛri/ MUUN-dəl-VERR-ee; Norse: Mundilfäri), or Saturn XXV (25), is a natural satellite of Saturn. It was discovered by Brett J. Gladman, et al. in 2000, and given the temporary designation S/2000 S 9. Mundilfari is about 7 kilometres in diameter, and orbits Saturn at an average distance of 18,360 Mm in 928.806 days, at an inclination of 170° to the ecliptic (150° to Saturn's equator), in a retrograde direction and with an eccentricity of 0.198.
Mundilfari may have formed from debris knocked off Phoebe by large impacts at some point in the Solar System's history.
It was named in August 2003 from Norse mythology, where Mundilfari is the father of the goddess Sól and the god Mani.