A curve which has at least multiplicity 
at each point where a given curve (having only ordinary
singular points and cusps)
has a multiplicity 
is called the adjoint to the given curve. When the adjoint curve is of order 
, it is called a special adjoint curve.
Adjoint Curve
Explore with Wolfram|Alpha
References
Coolidge, J. L. A Treatise on Algebraic Plane Curves. New York: Dover, p. 30, 1959.Referenced on Wolfram|Alpha
Adjoint CurveCite this as:
Weisstein, Eric W. "Adjoint Curve." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/AdjointCurve.html