septentrĭōnālis — Lewis & Short
septentrĭōnālis, e, adj.septentriones, II.,
I of or belonging to the north, northern, north-:
pars (terrae), circulus,Varr. R. R. 1. 2, 4; Vitr. 9, 6:
plaga,Sen. Q. N. 4, 5, 2:
latus,id. ib. 5, 16, 6; Plin. 2, 70, 70, § 177:
oceanus,id. 9, 17, 30, § 64:
venti,Col. 11, 2, 21.—Plur. subst.: sep-tentrĭōnālĭa, ĭum, n., the northern regions, Plin. 11, 14, 14, § 33:
Africae et Numidiae,id. 6, 34, 39, § 213:
Britanniae,Tac. Agr. 10.