Source : Webster's Revised Unabridged Dictionary (1913)

Node \Node\, n. [L. nodus; perh. akin to E. knot. Cf. {Noose},
   {Nowed}.]
   1. A knot, a knob; a protuberance; a swelling.

   2. Specifically:
      (a) (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.
      (b) (Bot.) The joint of a stem, or the part where a leaf
          or several leaves are inserted.
      (c) (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.
      (d) (Geom.) The point at which a curve crosses itself,
          being a double point of the curve. See {Crunode}, and
          {Acnode}.
      (e) (Mech.) The point at which the lines of a funicular
          machine meet from different angular directions; --
          called also {knot}. --W. R. Johnson.
      (f) (poet.) The knot, intrigue, or plot of a piece.
      (g) (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.
      (h) (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.
      (i) (Zo["o]l.) A swelling.

   {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 {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.

Source : WordNet®

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