Nodal point
A nodal point is a spot on a vibrating object that stays nearly still while the rest of it moves. For a free bar in its first bending mode, the two nodal points sit about 22 percent of the length in from each end. Supporting an object at its nodal points lets it vibrate freely without shaking its mounts.
Example: Xylophone bars are held up by cords at their nodal points so they ring clearly instead of being muffled.