And behold, another beast
came up, a second one, like a bear; and it was raised up on one side, and three ribs were in its mouth between its teeth; and they said thus to it, ‘Arise, devour much flesh.’

“a bear” The bear is the Medo-Persian Empire, and it is raised up on one side because in the confederation of Persia and Media, Persia was always the dominant power.