Of or pertaining to a bear or bears: as, an ursine genus; related to the bear; arctoid: as, the ursine series of Carnivora; resembling a bear or what relates to a bear: as, an ursine walk.In entomology, thickly clothed with long, bristle-like, erect hairs: applied especially to certain lepidopterous larvæ.n. A bear; any member of the family Ursidæ.