Lewis & Short

Ardŭenna, ae (Ardenna, Ven. Fort. Carm. 7, 4), f. [v. arduus; cf. Welsh ardh, to raise up], the forest-covered mountains in Gaul, now Ardennes, Caes. B. G. 5, 3; 6, 29 Herz.; Tac. A. 3, 42; cf. Mann. Gall. p. 203.