metacenter -
(shipbuilding) the point of intersection between two vertical lines, one line through the center of buoyancy of the hull of a ship in equilibrium and the other line through the center of buoyancy of the hull when the ship is inclined to one side; the distance of this intersection above the center of gravity is an indication of the stability of the ship
metacenter -
A midway point between a ship's centre of buoyancy when upright and its centre of buoyancy when tilted; it must be above the centre of gravity to enable a tilting ship to return to an upright position.