Bilge

1. The part of the hull that the ship rests on if it takes the ground; the outer end of the floors. The "turn of the bilge" is the part of the hull that changes from the (approximately) vertical sides of the hull to the more horizontal bottom of the ship.
2. (Usually in the plural: "bilges") The compartment at the bottom of the hull of a ship or boat where water collects and must be pumped out of the vessel; the space between the bottom hull planking and the ceiling of the hold.
3. To damage the hull in the area of the bilge, usually by grounding or hitting an obstruction.
4. To fail an academic course ("bilge") or curriculum ("bilge out").