This meaning refers to the vessel's central lower structure, which provides strength and stability.
The ship's keel was laid in the new dockyard.
The damaged keel affected the boat's stability.
This meaning refers to a fin-like lower structure that adds balance and resists sideways movement.
The yacht has a deep keel.
The keel prevents the boat from sliding sideways.
Usually used as keel over, this meaning describes falling, fainting, or overturning suddenly.
He keeled over from exhaustion.
The small boat keeled sideways in the wind.
