node

– noun
1. a knot, protuberance, or knob.
2. a centering point of component parts.
3. a. a joint in a stem.
b. a part of a stem that normally bears a leaf.
4. a point on a curve or surface at which there can be more than one tangent line or tangent plane.
5. a point, line, or region in a standing wave at which there is relatively little or no vibration.
6. either of the two points at which the orbit of a heavenly body intersects a given plane, esp. the plane of the ecliptic or of the celestial equator.