降交点

[ noun ]
the point at which an orbit crosses the ecliptic plane going south
<noun.location>

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:
(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.

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.
[PJC]

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

{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.