Mechanics: A wobbling motion of a spinning rigid body, such as a top,
as it precesses about its vertical axis.
Fromm L. nutation-, from nutat(us), p.p. of nutare "to wobble, to sway, to nod repeatedly," from nu "nod" + -ta frequentative suffix + -tus p.p. ending + -ion a suffix denoting action or condition.
Kaltâv, from Kermâni keletow, Malâyeri kallatow "wobbling," from kal, kalleh "head" + tâv, tow, tâb "swing, twist," from tâbidan "to twist, to spin."
nutation in right ascension
Fr.: nutation en ascension droite
Same as → equation of the equinoxes.