1.NounThe vertical distance between the metacentre and center of mass (conventionally taken to be positive when the metacentre is above the center of mass, and negative when the center of mass is above the metacentre) of a vessel (such as a ship or a boat) when the vessel is upright with zero bank angle; measures the vessel's tendency to resist being rolled from the upright orientation; must be positive in order for the vessel to have positive static stability.