Ruled paper is paper with straight lines printed across it, so your writing stays even. The lines usually run from left to right, like the lines in a school notebook. Teachers often ask for ruled paper or lined paper — they mean the same kind of thing. It is not paper that a king “rules.” The word comes from an older sense of rule: a straight stick, or the line you draw with it. Graph paper has squares; ruled paper has simple parallel lines. You will see it on notebooks, exam booklets, and writing pads. It is a quiet, practical word. Nobody uses it to sound grand.