A slight, slow, nodding motion of the earth's axis of rotation which is superimposed on the precession of the equinoxes; it is the combination of a number of perturbations (lunar, solar, and fortnightly nutation).

The rhythmic change in the position of growing plant organs caused by variation in the growth rates on different sides of the growing apex.

A bobbing or nodding up-and-down motion of a spinning rigid body, such as a top, as it precesses about its vertical axis.