node

noun

a knot; knob; swelling
a point of concentration; central point
Anat. a knotty, localized swelling; protuberance
Astron. either of the two diametrically opposite points at which the orbit of a celestial body intersects a reference plane, as the ecliptic
Bot. that part, or joint, of a stem from which a leaf starts to grow
Geom. the point where a continuous curve crosses or meets itself
Physics the point, line, or surface of a vibrating object, as a string, virtually free of vibration

See node in American Heritage Dictionary 4