Parallel lines are defined as lines that are equal distance apart and never touch. Being an equal distance apart is also known as equidistant. Parallel lines always point in the same direction.
For a visual representation of parallel lines, small arrow marks are drawn on lines that are parallel. If the plane depicting the parallel lines consists of two sets of parallel lines, the second is represented by two arrow marks on each line.
Pairs of angles can be created by crossing parallel lines with another line segment, called a transversal. This creates eight angles. These angles include vertical, corresponding, alternate interior and alternate exterior angles.