QUADRISECT.—To divide into four equal parts.
SECTION.—A projection upon a plane parallel to a cutting plane which intersects any object. The section generally represents the part behind the cutting plane, and represents the cut surfaces by diagonal lines.
SECTIONAL.—Showing the section made by a plane.
SHADOW.—Shade and shadow have about the same meaning.
SOLID.—A solid has three dimensions—length, breadth and thickness.
SPHERE.—A solid bounded by a curved surface every point of which is equally distant from a point within called the center.
SURFACE.—The boundary of a solid. It has but two dimensions—length and breadth. Surfaces are plane or curved.
A Plane Surface is one upon which a straight line can be drawn in any direction.
A Curved Surface is one no part of which is plane.
The surface of the sphere is curved in every direction, while the curved surfaces of the cylinder and cone are straight in one direction.