any of several medium-sized to large bears of the species Ursus arctos, inhabiting North America and Eurasia in dwindling populations, characterized by an upturned muzzle and a hump high on the back and ranging from light tan to near black; formerly considered three distinct species and often still referred to as such:the grizzly bear; U. middendorffi, the Kodiac bear; and U. arctos, comprising European and Asian brown bears. U. horribilis,