Lewis & Short

tertĭānus, a, um, adj. [tergeo], of or belonging to the third, tertian.

  1. I. Adj.: tertianae febres, i.e. the tertian fever, Cic. N. D. 3, 10, 24.
  2. II. Substt.
    1. A. tertĭāna, ae, f. (sc. febris), the tertian fever, Cels. 3, 5; Petr. 17; Plin. 24, 19, 107, § 170: tertianis et quartanis remedium, id. 21, 23, 94, § 166; 22, 25, 72, § 150.
    2. B. tertĭāni, ōrum, m. (sc. milites), soldiers of the third legion, Tac. A. 13, 38; id. H. 3, 24.