† hyperˈboreal,a.Obs.rare. [f. hyper- 1 + boreal; cf. next.] = next A. 1. 1596R. L[inche]Diella (1877) 80 Whiter then snow on Hyperboreall hyll.c1790A. Bell in Southey Life (1844) I. 122 In that cold climate, so congenial to my hyperboreal constitution.