Two or more lines or line segments which are perpendicular are said to be orthogonal.
Orthogonal Lines
See also
Orthogonal Curves, Perpendicular, Right AngleExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Orthogonal Lines." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/OrthogonalLines.html