A reddish celestial body about half the size of earth's moon. It is the most distant known object in the solar system and orbits the sun every 10,500 years.
Definition of Sedna in US English:
Sedna
proper nounˈsednə
Astronomy
A reddish celestial body about half the size of earth's moon. It is the most distant known object in the solar system and orbits the sun every 10,500 years.