Lewis & Short

sŏnōrus, a, um (collat. form sŏnōris, e, Diom. 497 and 498), adj. [sonor], noisy, loud, sounding, resounding, sonorous (poet. and in post-Aug. prose for the class. sonans): cithara, Tib. 3, 4, 69: aes, Claud. IV. Cons. Hon. 149: arcus, id. in Ruf. 2, 80: tempestates sonoras, Verg. A. 1, 53: tonitru, Claud. Laud. Stil. 2, 26: pelage, Lucr. 5, 35 Lachm.: flumina, Verg. A. 12, 139: nemus, Stat. Th. 4, 34: Phocis (on account of the Delphic oracle), id. ib. 11, 281: insula fluctibus, Claud. B. Gild. 512: versus qui crepitant pronuntiatione fragosā et exsultantem informant dictionem, ut (Verg. A. 9, 503): at tuba terribilem, etc., Diom. p. 498 P.
* Adv.: sŏnōrē, loudly: oscitavit (with clare), Gell. 4, 20, 8.