1. A state of inactivity and metabolic depression in endotherms. Hibernation refers to a season of heterothermy that is characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Although traditionally reserved for “deep” hibernators such as rodents, the term has been redefined to include animals such as bears and is now applied based on active metabolic suppression rather than based on absolute body temperature decline. (wikipedia.org)
2. A state of inactivity and metabolic depression in animals during winter. (wiktionary.org)
3. Cessation from or slowing of activity during the winter; especially slowing of metabolism in some animals; the torpid or resting state in which some animals pass the winter; a state of dormancy used by animals in the colder winter months where metabolism is slowed down and expenditure of energy is therefore reduced. This is done mostly due to the fact that food sources are scarce at this time of the year, and if the animal did not hibernate, it would more than likely have a greater expenditure of energy looking for food than the energy gained by finding it. (biology-online.org)
4. The act of retiring into inactivity. (biology-online.org)
Word origin: 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” (cf. Sanskrit heman “in winter,” Hittite gimmanza, Greek kheima, Old Church Slavonic zima, Lithuanian žiema “winter”).