'Fort' in the Bible

So David dwelt in the fort, and called it the city of David. And David built round about from Millo and inward.

And the fortress of the high fort of thy walls shall he bring down, lay low, and bring to the ground, even to the dust.

And lay siege against it, and build a fort against it, and cast a mount against it; set the camp also against it, and set battering rams against it round about.

At his right hand was the divination for Jerusalem, to appoint captains, to open the mouth in the slaughter, to lift up the voice with shouting, to appoint battering rams against the gates, to cast a mount, and to build a fort.

He shall slay with the sword thy daughters in the field: and he shall make a fort against thee, and cast a mount against thee, and lift up the buckler against thee.

Then he shall turn his face toward the fort of his own land: but he shall stumble and fall, and not be found.