A trinary star cluster was a type of star cluster consisting of a Trinary star system.
In 2151, Jonathan Archer expressed disbelief that the Vulcans had limited information about the area of space along the course of Enterprise NX-01, that nothing had garnered their interest like a sentient species or a trinary star cluster. (ENT: "Fight or Flight")
Later that year, Elizabeth Cutler pointed out Sol, located left of a trinary cluster, from the surface of Archer IV for Trip Tucker. (ENT: "Strange New World")