Tau Ceti III, or Kaferia, was an inhabited third planet orbiting the star Tau Ceti. This star, located in the Alpha Quadrant, was approximately eight light years from Sol. (TNG: "The Naked Now", production art)
|Tau Ceti system|
|Tau Ceti Prime • Tau Ceti III • Tau Ceti IV|
"tow (rhymes with cow)- set-ee 3" was the pronunciation for Tau Ceti III from the script pronunciation guide.
According to The Worlds of the Federation (p. 112), Tau Ceti III was also known as Kaferia and to the natives as Kohath-Seredi. It was the planet from which Kaferian apples came, and also hosted the Kaferians, an insectoid species. Kaferia and Kaferians were also mentioned in various other novels and sources, and Kaferians were made canon when a labeled illustration from the FASA RPG module The Federation was used in an okudagram seen in "The Big Goodbye". The planet originating Kaferian apples is alluded to in "Where No Man Has Gone Before", and it is indicated that Gary Mitchell visited it multiple times, but it is not named in the episode.
According to Star Trek: Star Charts (p. 44) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Kaferia (Tau Ceti) system, in the late 24th century, was a Federation system, with Tau Ceti III listed as a member.