hi ‧ ber ‧ nate /ˈhaɪbəneɪt $ -ər-/ BrE AmE verb [intransitive]
[ Date: 1800-1900 ; Language: Latin ; Origin: past participle of hibernare 'to pass the winter' , from hibernus 'of the winter' ]
if an animal hibernates, it sleeps for the whole winter
—hibernation /ˌhaɪbəˈneɪʃ ə n $ -bər-/ noun [uncountable]