### Theory:

$$m$$ and $$n$$  are any two non-parallel lines and $$l$$  is another line intersecting them at $$A$$   and $$B$$.

Such intersecting line ($$l$$) is called as transversal line.

A transversal line is a line that intersects two lines at distinct points.

NOTE:

The line $$l$$   is not a transversal to the lines $$m$$   and $$n$$,    but it is a transversal to the pair of lines $$m$$ and $$o$$ , $$n$$ and $$o$$.

Line $$l$$ does not intersect the lines $$m$$ and $$n$$ at distinct points. So, it is not a transversal line.