Orthogonal Curves
Two (or more) intersecting curves that are perpendicular at their intersection are said to be orthogonal.
See also
Orthogonal, PerpendicularExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Orthogonal Curves." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/OrthogonalCurves.html