meta·cen·ter /ˈmɛtəˌsɛntɚ/
  定傾中心
  Met·a·cen·ter or Met·a·cen·tre, n.  Hydrostatics The point of intersection of a vertical line through the center of gravity of the fluid displaced by a floating body which is tipped through a small angle from its position of equilibrium, and the inclined line which was vertical through the center of gravity of the body when in equilibrium.
  Note: ☞ When the metacenter is above the center of gravity, the position of the body is stable; when below it, unstable.
  ◄ ►
  metacenter
       n : (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 [syn: metacentre]