Surface
in mathematics, the boundary of a solid, having two dimensions, length and breadth. It may be conceived to be generated by the motion of a straight or curved line, just as a curve is generated by the motion of a point.
Of all surfaces, the most important are those of the second order, wh tersected by a straight line in at most two points, and whose curve of section by a plane is which are included among the so-called quadric sur- the limiting case of two planes, are in- spheres, cones, and cylinders, and also Hyperboloids, ellipsoids, paraboloids, is a curve of the second order. spheres, cones, and cylinders, and also the limiting case of two planes, are included among the so-called quadric surfaces.