I.a stalk, stem of a plant.
II. Transf.
A. A staff twined round with ivy and vine-shoots, borne by Bacchus and the Bacchantes; the Bacchic staff, thyrsus, Hor. C. 2, 19, 8; Ov. M. 3, 542; 3, 712; 4, 7; 9, 641; 11, 28; Stat. Th. 9, 614; Sen. Herc. Fur. 904; id. Oedip. 628 al. — Hence, poet. transf.,
B. A thorn, goad: “acri Percussit thyrso laudis spes magna meum cor,” Lucr. 1, 923; Ov. Tr. 4, 1, 43.