a long, narrow, flat piece of plastic, metal, or wood with straight edges where centimetres or inches, or both are printed. It is used for measuring things and for drawing straight lines
The architect used a ruler to draw precise lines on the blueprint.
Students are required to bring a ruler for geometry class to measure angles.
The tailor relied on a ruler to ensure accurate measurements for the custom suit.
In woodworking, a straight-edged ruler is essential for precise cuts.
