nutation

[ noo-tey-shuhn, nyoo- ]

noun

1. an act or instance of nodding one's head, especially involuntarily or spasmodically.
2. Botany. spontaneous movements of plant parts during growth.
3. Astronomy. the periodic oscillation observed in the precession of the earth's axis and the precession of the equinoxes.
4. Mechanics. the variation of the inclination of the axis of a gyroscope to the vertical.

nutation

/ njuːˈteɪʃən /

noun

1. astronomy a periodic variation in the precession of the earth's axis causing the earth's poles to oscillate about their mean position
2. physics a periodic variation in the uniform precession of the axis of any spinning body, such as a gyroscope, about the horizontal
3. Also calledcircumnutation the spiral growth of a shoot, tendril, or similar plant organ, caused by variation in the growth rate in different parts
4. the act or an instance of nodding the head

nutation

/ no̅o̅-tā′shən /

1. A small, cyclic variation of the Earth's axis of rotation with a period of 18.6 years, caused by tidal forces (mostly due to the gravity of the Moon). Nutation is a small and relatively rapid oscillation of the axis superimposed on the larger and much slower oscillation known as precession . Although discovered in 1728 by the British astronomer James Bradley (1693–1762), nutation was not explained until two decades later.
2. A slight curving or circular movement in a stem, as of a twining plant, caused by irregular growth rates of different parts.

Derived Forms

• nuˈtational, adjective

Other Words From

• nu·tation·al adjective

Word History and Origins

Origin of nutation¹

1605–15; < Latin nūtātiōn- (stem of nūtātiō ), equivalent to nūtāt ( us ) (past participle of nūtāre to nod repeatedly; nū- nod + -tā- frequentative suffix + -tus past participle ending) + -iōn- -ion; numen

Word History and Origins

Origin of nutation¹

C17: from Latin nutātiō, from nūtāre to nod

Example Sentences

Mathews, P. M., Herring, T. A. & Buffett, B. A. Modeling of nutation and precession: new nutation series for nonrigid Earth and insights into the Earth’s interior.

From Nature

Even the tides and precession of the equinoxes and Bradley's nutation were accounted for and explained.

From Project Gutenberg

Commonly this nutation is slight or hardly observable.

From Project Gutenberg

Either it may point to a different star, remaining fixed relatively to the earth, as in the nutation which Bradley discovered; or it may actually change its position in the earth.

From Project Gutenberg

This angle of tilt may be assumed to be constant, for I won't bother with the precessions, nutations and other minor movements considered in accurate computations.

From Project Gutenberg