What is "hibernacle"

Hibernacle \Hi*ber"na*cle\, n. [L. hibernaculum a winter residence, pl. hibernacula winter quarters: cf. F. hibernacle. See Hibernate.] That which serves for protection or shelter in winter; winter quarters; as, the hibernacle of an animal or a plant.
--Martyn.

"winter residence," 1708, from Latin hibernaculum "winter residence, winter quarters," related to hibernare "to winter" (see hibernation) with instrumentive suffix -culum. Related: Hibernacular.

n. 1 That which serves as a winter retreat. 2 Winter quarters. 3 The place where an animal hibernates.