Lewis & Short

tŭba, ae, f. [kindr. with tubus, a tube], a trumpet, esp. a war-trumpet (straight, while the cornu was curved, Acron ad Hor. C. 1, 1, 23).

  1. I. Lit.: ille arma misit, cornua, tubas, falces, Cic. Sull. 5, 17: tubae et signa militaria, id. Cat. 2, 6, 13: at tuba terribili sonitu taratantara dixit, Enn. ap. Prisc. p. 842 P. (Ann. v. 452 Vahl.); imitated by Verg. A. 9, 503: tubae utrimque canunt, Plaut. Am. 1, 1, 73: signum tubā dare, Caes. B. G. 2, 20; so id. ib. 7, 81; id. B. C. 3, 46; 3, 90; Liv. 29, 27, 5 al.; cf. also Caes. B. G. 7, 47; Hirt. B. G. 8, 20: non tuba directi, non aeris cornua fiexi, Ov. M. 1, 98; Tac. A. 1, 68; Luc. 4, 750; 6, 130; 7, 477; Sil. 5, 12 al.; v. Veg. Mil. 3, 5.
    Apart from military purposes, it was used on various occasions, as at religious festivals, games, funerals, etc., Varr. L. L. 6, § 14 Müll.; Ov. F. 1, 716; Verg. A. 5, 113; Juv. 10, 214; Stat. S. 3, 1, 139 al.; cf. tubus, II. A.; Verg. A. 11, 192; Ov. H. 12, 140; Hor. S. 1, 6, 44; Pers. 3, 103; cf. Atei. Capito ap. Gell. 20, 2, 3.
    1. B. Transf.
      1. 1. A signal for war, war, Claud. Rapt. Pros. 1, 64; id. Laud. Stil. 1, 246; Mart. Spect. 28, 2.
      2. 2. A loud sound: nimborum, i. e. the roar of thunder, Claud. gigant. 60.
        1. b. Sonorous, elevated epic poetry, Mart. 8, 3, 22; 8, 56, 4; 10, 64, 4; 11, 3, 8; Claud. Cons. Prob. et Olybr. 197.
        2. c. A lofty style of speaking, Prud. contr. Symm. 2, 68; Sid. Ep. 4, 3 fin.
  2. II. Trop.: tuba belli civilis, i. e. exciter, author, instigator, Cic. Fam. 6, 12, 3: rixae, Juv. 15, 52.