'Fortress' in the Bible

And I saw in the vision; and it came to pass, when I saw, that I was in the fortress of Shushan, which is in the province of Elam. And I saw in the vision, and I was by the river Ulai.

But out of a shoot from her roots shall one stand up in his place, who shall come to the army, and shall enter into the fortress of the king of the north, and shall deal against them, and shew himself mighty.

And his sons shall be stirred up, and shall assemble a multitude of great forces; and one shall certainly come, and overflow, and pass through; and he shall return and carry the war even to his fortress.

And forces shall stand on his part, and they shall profane the sanctuary, the fortress, and shall take away the continual sacrifice, and they shall place the abomination that maketh desolate.