from The Century Dictionary.
- noun In Roman antiquity: A leather wine-skin. A measure of capacity equal to 20 amphoræ. The “sack”: a punishment appointed for parricides, who, after being flogged and undergoing other indignities, were sewed up in a leather bag and cast into the sea.
- noun The scrotum.
Sorry, no etymologies found.
The murderer of a parent was sewed up in a sack (culeus or culleus) and thrown into a river.