Lewis & Short

sūber, ĕris, n.,

  1. I. the cork-oak, cork-tree: Quercus suber, Linn.; Plin. 16, 8, 13, § 34; 16, 25, 41, § 98; Col. 4, 26, 1; 9, 6, 1; Verg. A. 7, 742.
  2. II. Transf., cork: silvestre, Verg. A. 11, 554; cf.: ut ramale vetus vegrandi subere coctum, i. e. a thick bark, like that of the cork-tree, Pers. 1, 97.
    The tree is called sūbĕrĭes, ēi, f., Lucil. ap. Fest. p. 294 Müll.; cf. Isid. Orig. 17, 7, 27.