The '''[[distance]] between two [[ParallelLine (geometry)|parallelstraight lines]]''' in the plane is the minimum distance between any two points lying on the lines. In case of intersecting lines, the distance between them is zero, because the minimum distance between them is zero (at the point of intersection); whereas in case of two [[LineParallel (geometry)|linesparallel]]'''inlines, the planeit is the perpendicular distance from a [[Point (geometry)|point]] on one line to the other line.
