'Millstone' in the Bible

"Don't take a pair of millstones, especially the upper millstone, as collateral for a loan, because this means taking a man's livelihood.

But a certain woman threw an upper millstone down on Abimelech's head, fracturing his skull.

Who killed Jerubbesheth's son Abimelech? Didn't a woman kill him by throwing an upper millstone on him from the wall at Thebez? Why did you go so close to the wall?' then tell him, "Your servant Uriah the Hittite also died.'"

His heart is as strong as stone, it is as hard as a lower millstone.

Our young men must grind grain with a millstone; our youths stumble under the weight of wood.