'Pillar' in the Bible

Now behold, I have made you today as a fortified city and as a pillar of iron and as walls of bronze against the whole land, to the kings of Judah, to its princes, to its priests and to the people of the land.

As for the pillars, the height of each pillar was eighteen cubits, and it was twelve cubits in circumference and four fingers in thickness, and hollow.

Now a capital of bronze was on it; and the height of each capital was five cubits, with network and pomegranates upon the capital all around, all of bronze. And the second pillar was like these, including pomegranates.