a geometric element that has position but no extension

(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

the point of intersection of lines or the point opposite the base of a figure

the common intersection of the three altitudes of a triangle or their extensions or of the several altitudes of a polyhedron provided these latter exist and meet in a point.