diagonal line
nounUK /daɪˈæɡənəl laɪn/
US /daɪˈæɡənəl laɪn/
A diagonal line is a straight line that slants from one corner to another.
She drew a diagonal line across the square to split it into two triangles.
OTHER MEANINGS
2. A line joining two non-adjacent vertices of a polygon.
The square has two diagonals that cross in the middle.
3. A line in a matrix or table running from top-left to bottom-right.
The numbers along the diagonal line of the grid are all ones.
4. A slanted direction or course.
The path cut a diagonal line through the field.