Zeta

Zeta was a letter in the Greek language alphabet of Earth, originating in the early period of human history.

It was used in the following contexts:

Doctor Who Universe

 * Zeta Minor (TV: Planet of Evil)
 * Zeta Cancri (PROSE: K9 and the Zeta Rescue)
 * Zeta Reticuli Four (PROSE: First Frontier)
 * Zeta Major, an asteroid (PROSE: Zeta Major)

Behind the scenes

 * Zeta Major (novel), a BBC Past Doctor Adventures novel
 * K9 and the Zeta Rescue, a book in The Adventures of K9 series
 * Project Zeta Sigma, an unproduced serial that would have been the first story of the Fifth Doctor (REF: Doctor Who - The Handbook: The Fifth Doctor)