'Twelve' in the Bible

Now Jehoram the son of Ahab began to reign over Israel in Samaria the eighteenth year of Jehoshaphat king of Judah, and reigned twelve years.

He put to the sword twelve thousand men of Edom in the Valley of Salt, and took Sela in war, naming it Joktheel, as it is to this day.

In the thirty-ninth year of King Azariah's reign over Judah, Menahem son of Gadi became king over Israel. He reigned for twelve years in Samaria.

Manasseh was twelve years old when he began to reign, and reigned fifty and five years in Jerusalem. And his mother's name was Hephzibah.

He got rid of the idolatrous priests whom the kings of Judah had ordained to burn incense [to pagan gods] in the high places in Judah’s cities and all around Jerusalem—also those who burned incense to Baal, to the sun, to the moon, to the constellations [of the zodiac], and to all the [starry] host of heaven.

The bronze of the items that King Solomon made for the Lord's temple -- including the two pillars, the big bronze basin called "The Sea," the twelve bronze bulls under "The Sea," and the movable stands -- was too heavy to be weighed.