1660s, from Latin hibernationem (nominative hibernatio) "the action of passing the winter," noun of action from past participle stem of hibernare "to winter, pass the winter, occupy winter quarters;" related to hiems "winter," from PIE *gheim- "snow, winter" (cognates: Sanskrit heman "in winter," Hittite gimmanza, Greek kheima, Old Church Slavonic zima, Lithuanian žiema "winter").