Search Result for "sedna": 
Wordnet 3.0

NOUN (1)

1. a planetoid of rock and ice about three-quarters the size of Pluto discovered in 2003; the most distant object known to orbit around the sun; 



WordNet (r) 3.0 (2006):

Sedna
    n 1: a planetoid of rock and ice about three-quarters the size
         of Pluto discovered in 2003; the most distant object known
         to orbit around the sun