Node

In geometry an oval figure formed by the intersection of one branch of a curve with another; in astronomy one of the two opposite points at which the orbit of a planet or comet intersects the plane of the ecliptic.

Ascending Node. The node which a planet, etc., crosses from south to north.

Descending Node. The node which a planet, etc., crosses from north to south.

Line of the Nodes. A straight line joining the two nodes.