Terrelians were a humanoid species native to the Alpha or Beta Quadrant. During the mid-23rd century a Terrelian diplomat and his daughter, Jara, were assigned to Vulcan. During their stay, Jara was granted a seat at Tuvok's school, after which he developed an emotional attraction toward her. (VOY: "Gravity") Members of this species later visited Deep Space 9 in 2371. Odo intended to conduct an investigation on them following the discovery of a covert surveillance device in one of the stations corridors, later determined to be planted by the Klingons. (DS9: "Visionary")