Definition
The line of nodes is the intersection of the orbital plane with the reference plane (ecliptic). It passes through both the ascending and descending nodes and rotates slowly due to perturbations — lunar node regression takes ~18.6 years.
Line of Nodes
The intersection line of an orbit plane with the reference plane.
3D illustration
The node axis is the intersection of the orbital plane with the ecliptic.
Use the menu and time controls to explore. Based on Jean Meeus' Astronomical Algorithms.