What is "descending node"

Node \Node\ (n[=o]d), n. [L. nodus; perh. akin to E. knot. Cf. Noose, Nowed.]

1. A knot, a knob; a protuberance; a swelling.

2. Specifically:

   1. (Astron.) One of the two points where the orbit of a planet, or comet, intersects the ecliptic, or the orbit of a satellite intersects the plane of the orbit of its primary.

   2. (Bot.) The joint of a stem, or the part where a leaf or several leaves are inserted.

   3. (Dialing) A hole in the gnomon of a dial, through which passes the ray of light which marks the hour of the day, the parallels of the sun's declination, his place in the ecliptic, etc.

   4. (Geom.) The point at which a curve crosses itself, being a double point of the curve. See Crunode, and Acnode.

   5. (Mech.) The point at which the lines of a funicular machine meet from different angular directions; -- called also knot.
      --W. R. Johnson.

   6. (Poet.) The knot, intrigue, or plot of a piece.

   7. (Med.) A hard concretion or incrustation which forms upon bones attacked with rheumatism, gout, or syphilis; sometimes also, a swelling in the neighborhood of a joint.
      --Dunglison.

   8. (Mus) One of the fixed points of a sonorous string, when it vibrates by aliquot parts, and produces the harmonic tones; nodal line or point.

   9. (Zo["o]l.) A swelling.

3. (Math., Computers) A special point in a graph or diagram which is attached to other points by links. It is often labeled and represented graphically as a box or circle. A node may represent any object which is related to other objects in a conceptual structure that can be represented as a graph, the relations being represented as links between the nodes.

4. (Anat.) A small mass of tissue differing from other tissue in its immediate vicinity; as, a lymph node.

   Ascending node (Astron.), the node at which the body is passing northerly, marked with the symbol [astascending], called the Dragon's head. Called also northern node.

   Descending node, the node at which the body is moving southwardly, marked thus [astdescending], called Dragon's tail.

   Line of nodes, a straight line joining the two nodes of an orbit.

Descending \De*scend"ing\, a. Of or pertaining to descent; moving downwards.

Descending constellations or Descending signs (Astron.), those through which the planets descent toward the south.

Descending node (Astron.), that point in a planet's orbit where it intersects the ecliptic in passing southward.

Descending series (Math.), a series in which each term is numerically smaller than the preceding one; also, a series arranged according to descending powers of a quantity.

n. the point at which an orbit crosses the ecliptic plane going south [ant: ascending node]