A hibernaculum, as you may have guessed from its similarity to the word hibernate, has something to do with animals that go dormant during the winter. (The Latin, hibernare, means to pass the winter.) A hibernaculum is the shelter where such an animal can hunker down and stay safe. A hibernaculum can be a cave for a bear, a woodchuck's burrow, even the cuccoon of a caterpillar stuck on a twig! Hibernaculua are all around us, all the time, but the word didn't come into usage until the end of the 1700s.
In these COVID-19 times I feel very much as though my room/hibernaculum has extended its presence into the spring.... Hopefully with some additional exercise and some good sunshine it will remain a comforting, safe, and healthy place!
–C