The Collaborative International Dictionary of English v.0.48:
Hibernal \Hi*ber"nal\, a. [L. hibernalis, from the root of hiems winter; akin to Gr. ? snow, Skr. hima cold, winter, snow: cf. F. hibernal.] Belonging or relating to winter; wintry; winterish. --Sir T. Browne. [1913 Webster]WordNet (r) 3.0 (2006):
hibernal adj 1: characteristic of or relating to winter; "bears in brumal sleep" [syn: brumal, hibernal, hiemal]