The Trialus system was a planetary system in the Gamma Quadrant. It had only one planet named Meridian. A millennia ago, an expedition to this system became stranded on the planet. In 2371, the USS Defiant was on an expedition into an uncharted sector in the quadrant when it detected unusual gravimetric distortions coming from this system. Investigating the distortions, the planet Meridian was discovered. That year, the planet only appeared in the system for twelve days. (DS9: "Meridian")