Theta Zibal III was the inhabited third planet of its star system. It was the homeworld of the warp-capable humanoid Zibalians.
One of the cities on this planet was named Tomobiki City. The planet was mentioned in the Federation biographical database file of Kivas Fajo. (TNG: "The Most Toys" okudagram)
This planet was only mentioned in writing.
In the Bayer designation, which was a system of stellar classification, the Greek letter indicated the brightness of a star in a constellation. In this case, Theta Zibal would be the 8th brightest star in its constellation.