Lewis & Short

Thȳiăs (dissyl.) or Thȳăs, ădis, f., = Θυιάς or Θυάς, a Bacchante, Verg. A. 4, 302; Hor. C. 3, 15, 10; Stat. Th. 5, 92.
More freq. in plur.: Thȳiădes or Thȳădes, um, Bacchantes, Cat. 64, 392; Hor. C. 2, 19, 9; Ov. F. 6, 514; Stat. Th. 12, 791.