Trigonis was a planet in a trinary star system located somewhere within the the galaxy's Alpha or Beta Quadrants.
History and specifics[]
Trigonis was noted as a bountiful source of silver deposits.
In the year 2268, Hikaru Sulu joked in the recreation room aboard the Federation starship USS Enterprise about a werewolf living on a planet with four moons. Nyota Uhura countered by saying that a vampire would have a difficult time on Trigonis because of all the silver there. (TOS novel: Ghost-Walker)