binode

Century Dictionary and Cyclopedia

1. n. In mathematics, a singularity of a surface consisting of a point at which there are two tangent planes. In the surface shown in fig. 1 each of these planes is tangent along the whole length of a line; but this circumstance is not a necessary concomitant of the singularity.
2. n. A crunode formed by the crossing of two branches of a curve.