Definitions [9]
Point: A point is a mark of position. It has neither length, width, nor thickness and occupies no space. It is usually denoted by a capital letter.
Three or more points that all lie on the same straight line

Three or more points that do not lie on the same straight line.

A line segment is part of a line between two endpoints. A line segment AB is generally denoted by the symbol `bar"AB"`.

A line is a straight path that extends infinitely in both directions and has only length, without width or thickness.

When two or more lines pass through the same point, they are called concurrent lines. The common point through which they pass is called the point of concurrence, i.e., point O.
A ray is a portion of a line that begins at a fixed point, called its origin, and extends infinitely in one direction.

When two lines intersect, and the angle between them is a right angle, then the lines are said to be perpendicular.
In mathematics, the relationship of perpendicularity is denoted by the symbol ⊥.
If Line A and Line B are perpendicular, the relationship is written as AB ⊥ PQ.

If a line or line segment divides an angle into two equal angles, then the line or line segment is called the angle bisector of the given angle.
