Coincident Lines
Two lines that lie on top of one another are called coincident lines.
See also
Coincident, Intersecting Lines, Parallel Lines, Skew LinesExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Coincident Lines." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CoincidentLines.html