1)
What is "Keren Mo'av"?
1.
Radak, Malbim, Targum Yonasan: It is the kingship. Radak - the horn is higher than all [other] limbs of the animal, therefore the kingship is called Keren, for its level is higher than the entire nation.
2)
What is "Zero'o"?
1.
Radak: Its officers and soldiers. They are the arm of the king and the nation, and their strength. This is like "u'Zero'os ha'Negev" (Daniel 1:15).
2.
Radak citing Targum Yonasan: Their authority.
3.
Malbim: The army and the fortresses.
