Alpha/Beta Quadrant Overview
Beta Thoridar was a Beta Quadrant star.
In 2256, this star's location was labeled on the star chart "Alpha/Beta Quadrant Overview" in the ready room aboard the USS Discovery. This star was located within the territory of the Klingon Empire. (DIS: "Magic to Make the Sanest Man Go Mad", "The War Without, The War Within")
In late 2367, at the start of the Klingon Civil War, the House of Duras gathered a large fleet near this star while preparing to launch an offensive against Gowron's forces. (TNG: "Redemption")
In the episode "Magic to Make the Sanest Man Go Mad", the star's name was spelled "Beta Thoridor".
According to Star Trek: Star Charts (p. 61) and Stellar Cartography: The Starfleet Reference Library ("Stellar Cartography", pp. 27, 30; "Federation Historical Highlights, 2161-2385"), Beta Thoridor was a M-class star. According to a map of the Klingon Empire – prepared by the Scribe K'Tark for the Klingon High Council in the Year of Kahless 893 (2266} – Beta Thoridar was identified as a Klingon star.
The Star Trek Encyclopedia (4th ed., vol. 1, p. 81) identified Beta Thoridar as a planet.