Lewis & Short

Clūsĭum, ii, n.,

  1. I. one of the oldest and most important towns of Etruria, the residence of Porsenna, previously called Camars or Camers, now Chiusi, Liv. 5, 33, 4 sq.; 10, 25, 11; Varr. ap. Plin. 36, 13, 19, § 91; Verg. A. 10, 167 al.; Müll. Etrusk. 1, p. 102; 1, p. 233 sq.; 2, p. 342.
    Hence,
  2. II. Clūsīnus, a, um, adj., pertaining to Clusium, of Clusium: vulgus, Sil. 8, 480: fontes (cold baths), Hor. Ep. 1, 15, 9: far (of special whiteness and excellence), Col. 2, 6, 3: siligo, Plin. 18, 9, 20, § 87: pultes, Mart. 13, 8.
    In plur.: Clūsīni, ōrum, m., the inhabitants of Clusium, Liv. 5, 33, 1: novi, veteres, Plin. 3, 5, 8, § 52.