(1) Point: a point is that which has no parts nor magnitude.
(2) Line Segment: a line segment is length without thickness.
(3) Ends of a Line Segment: the ends of a line segment are points.
(4) Straight Line Segment: a straight line segment lies evenly between its end points.
(5) Surface: a surface is that which has length and width but not thickness.
(6) Extremities of a Surface: the extremities of a surface are line segments.
(7) Plane surface: a plane surface is such that if any two points in it are joined by a line, the line lies wholly in that surface.
(8) Parallel Lines: parallel lines are lines in the same plane surface which, if extended ever so far in both directions, would not meet.