Line of nodes

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. [1913 Webster]

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. [1913 Webster]

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. [1913 Webster]