nutation
/njuːˈteɪʃ(ə)n
/noun [mass noun]
1A periodic variation in the inclination of the axis of a rotating object.
1.1 Astronomy A periodic oscillation of the earth’s axis which causes the precession of the poles to follow a wavy rather than a circular path.There is a small periodic effect called nutation superimposed on precession caused by the motion of the perihelion of the Moon....
- In addition to the precession and nutation of the Earth's rotational axis, the Earth itself undergoes a wobble such that the crust wanders about the rotational axis with a combination of two periods and amplitudes.
- Bessel's work in determining the constants of precession, nutation and aberration won him further honours, such as a prize from the Berlin Academy in 1815.
2 Botany The circular swaying movement of the tip of a growing shoot.
Origin
Early 17th century (denoting nodding of the head): from Latin nutatio(n-), from nutare 'to nod'.