node

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A knob, knot, protuberance, or swelling.
• noun Medicine A small, well-defined mass of tissue that is either normal or pathological, as a lymph node or a node at an arthritic joint.
• noun A point or area where two lines, paths, or parts intersect or branch off.
• noun A focal point or a point of interaction.
• noun Botany The point on a stem where a leaf is attached or has been attached; a joint.
• noun Physics A point or region of virtually zero amplitude in a wave or periodic system.
• noun Mathematics The point at which a continuous curve crosses itself.
• noun Computers A terminal in a computer network.
• noun Either of two diametrically opposite points at which the orbit of a planet intersects the ecliptic.
• noun Either of two points at which the orbit of a satellite intersects the orbital plane of a planet.

from The Century Dictionary.

• noun A knot, or what resembles one; a knob; a protuberance.
• noun In pathol.:
• noun A hard swelling on a ligament, tendon, or bone.
• noun A hard concretion or incrustation on a joint affected with gout or rheumatism. Specifically
• noun In anatomy, a joint, articulation, or condyle, as one of the knuckles of the hand, bones being usually enlarged at their articular ends, thus constituting nodes or knotted parts between slenderer portions technically called internodes.
• noun In entomology, any knot-like part or organ.
• noun In botany, the definite part of a stem which normally bears a leaf, or a whorl of leaves, or in cryptogams, such as Equisetum and Chara, the points on the stem at which foliar organs of various kinds are borne. See cut in next column.
• noun In astronomy, one of the points in which two great circles of the celestial sphere, such as the ecliptic and equator, or the orbit of a planet and the ecliptic, intersect each other; especially, one of the points at which a celestial orbit cuts the plane of the ecliptic.
• noun In acoustics, a point or line in a vibratile body, whether a stretched string or membrane, a solid rod, plate, or bell, or a column of air, which, when the body is thrown into vibration, remains either absolutely or relatively at rest: opposed to loop.
• noun Figuratively, a knot; an entanglement.
• noun In dialing, a point or hole in the gnomon of a dial, by the shadow of or light, through which either the hour of the day in dials without furniture, or the parallels of the sun's declination and his place in the ecliptic, etc., in dials with furniture, are shown.
• noun In geom.:
• noun A point upon a curve such that any line passing through it cuts the curve at fewer distinct points than lines in general do.
• noun A double point of a surface; a point where there is more than one tangent-plane; especially, a conical point where the form of the surface in the infinitesimally distant neighborhood is that of a double cone of any order.
• noun A point of a surface: so called because it is a node of the curve of intersection of the surface with the tangent-plane at that point.

from the GNU version of the Collaborative International Dictionary of English.

• noun A knot, a knob; a protuberance; a swelling.
• noun (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.
• noun (Bot.) The joint of a stem, or the part where a leaf or several leaves are inserted.
• noun (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.
• noun (Geom.) The point at which a curve crosses itself, being a double point of the curve. See Crunode, and Acnode.
• noun (Mech.) The point at which the lines of a funicular machine meet from different angular directions; -- called also knot.
• noun (Poet.) The knot, intrigue, or plot of a piece.
• noun (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.
• noun (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.
• noun (Zoöl.) A swelling.
• noun (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.
• noun (Anat.) A small mass of tissue differing from other tissue in its immediate vicinity.
• noun (Astron.) the node at which the body is passing northerly, marked with the symbol ☊, called the Dragon's head. Called also northern node.
• noun the node at which the body is moving southwardly, marked thus ☋, called Dragon's tail.
• noun a straight line joining the two nodes of an orbit.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A knot, knob, protuberance or swelling.
• noun astronomy The point where the orbit of a planet, as viewed from the Sun, intersects the ecliptic. The ascending and descending nodes refer respectively to the points where the planet moves from S to N and N to S. The respective symbols are ☊ and ☋.
• noun botany A stem node.
• noun computer networking A computer or other device attached to a network.