In these verses, the angel explains to Daniel the symbolic meaning of the things he saw in his vision. The animals and horns actually represent human rulers and kingdoms. (See: [[rc://en/ta/man/jit/writing-symlanguage]])
These words could either 1) refer to the literal kings of Media and Persia or 2) be a metonym in which the kings represents the kingdoms of Media and Persia. Alternate translation: "the kingdoms of Media and Persia" (See: [[rc://en/ta/man/jit/figs-metonymy]])