A crunode, also known as an ordinary double point, of a plane curve is point where a curve intersects itself so that two branches of the curve have distinct tangent lines. The Maclaurin trisectrix, shown above, has a crunode at the origin.

# Crunode

## See also

Acnode, Ordinary Double Point, Spinode, Tacnode## Explore with Wolfram|Alpha

## Cite this as:

Weisstein, Eric W. "Crunode." From *MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/Crunode.html