Cartesian line
Else clues• Algebraic reference line
• Geometric vertical
• Graph component
• Graph line
• Graph part
• Graph vertical
• How height may be measured
• It goes up and down
• Line on a plane
• Part of a plane
• Plane part
• Plotter's line, perhaps
• Side of a Cartesian quadrant
• Vertical graph component
• Vertical graph line
• Vertical line on a graph
• Vertical number line, in geometry
• Vertical reference line on a graph