Definition of "node"

A knot, knob, protuberance or swelling.  examples

(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 South to North and N to S; their respective symbols are ☊ and ☋.  examples

(botany) A leaf node.  examples

(networking) A computer or other device attached to a network.  examples

(engineering) The point at which the lines of a funicular machine meet from different angular directions.  examples

(geometry) The point at which a curve crosses itself, being a double point of the curve. See crunode and acnode.  examples

(geometry) A similar point on a surface, where there is more than one tangent-plane.  examples

(graph theory) A vertex or a leaf in a graph of a network, or other element in a data structure.  examples

(medicine) 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.  examples

(physics) A point along a standing wave where the wave has minimal amplitude.  examples

(rare) The knot, intrigue, or plot of a dramatic work.

(technical) A hole in the gnomon of a sundial, 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.  examples

(computational linguistics) The word of interest in a KWIC, surrounded by left and right cotexts.  examples

(electronics) A region of an electric circuit connected only by (ideal) wires (i.e the voltage between any two points on the same node must be zero).  examples