Parallel lines
They are said to be parallel lines
If they are in the same plane, two lines that don't intersect are said to be "parallel".
Two lines that cross at a point are said to intersect. The point where they meet is called the point of intersection. If the lines are not parallel, they will always cross at exactly one point in a two-dimensional plane. In contrast, parallel lines never intersect and thus do not meet at any point.
Theorem: If two lines intersect, then exactly one plane contains both lines. So, when two or more lines intersect at one point, they lie exactly in the same plane. When two or more lines intersect at one point, their point of intersection satisfies all equations of those lines. In other words, the equations of these lines have the same solution, which is the point of intersection.
As for example perpendicular lines are non parallel lines.
Two lines of a plane are said to be parallel if they do not intersect and the perpendicular distance betweem them is always same.
In geometry a flat surface is usually called a plane surface, or just a plane. You use it like this.1) If straight lines lie in the same plane they a said to be co-planar.2) If two co-planar straight lines never intersect, they are parallel to each other.
I believe this is possibly called a vector. They begin at the same point, however, they do not run on the same plane, nor do the intersect. As I said, they do begin at the same point and form a triangle.
Lines that are equal distance from one another and never intersect are said to be parallel lines.
Concurrent lines
When two lines intersect to form a 90o angle, they are said to be perpendicular.
concurrent