NOUN (2)

1. (Greek mythology) the learned centaur who tutored Achilles, Asclepius, Hercules, Jason, and other heroes;

2. an asteroid discovered in 1977; it is unique in having an orbit lying mainly between the orbits of Saturn and Uranus;

WordNet (r) 3.0 (2006):

Chiron
    n 1: (Greek mythology) the learned centaur who tutored Achilles,
         Asclepius, Hercules, Jason, and other heroes
    2: an asteroid discovered in 1977; it is unique in having an
       orbit lying mainly between the orbits of Saturn and Uranus