Source : Webster's Revised Unabridged Dictionary (1913)

Hibernation \Hi`ber*na"tion\, n. [Cf. F. hibernation.]
   The act or state of hibernating. --Evelyn.

Source : WordNet®

hibernation
     n 1: the torpid or resting state in which some animals pass the
          winter
     2: cessation from or slowing of activity during the winter;
        especially slowing of metabolism in some animals
     3: the act of retiring into inactivity; "he emerged from his
        hibernation to make his first appearance in several years"