Node  n. 1  a part of a plant stem from which leaves emerge. B knob on a root or branch. 2  natural swelling. 3  either of two points at which a planet's orbit intersects the plane of the ecliptic or the celestial equator. 4  point of minimum disturbance in a standing wave system. 5 point at which a curve intersects itself. 6 component in a computer network.  nodal adj. [latin nodus knot]