nutation

American  

[noo-tey-shuhn, nyoo-] / nuˈteɪ ʃən, nyu- /

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.

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nutation British  

/ 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 called: circumnutation.  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

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nutation Scientific  

/ 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.

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Other Word Forms

• nutational adjective

Etymology

Origin of nutation

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; cf. numen

Example Sentences

But how many people are aware that pizzlesprung is a Kentucky word to describe the weary, or that nutation is the wobble in the earth's axis caused by the pull of the moon?

From Time Magazine Archive

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 Astronomical Discovery by Turner, Herbert Hall

The obliquity of the ecliptic affected with nutation.

From The Sailor's Word-Book An Alphabetical Digest of Nautical Terms, including Some More Especially Military and Scientific, but Useful to Seamen; as well as Archaisms of Early Voyagers, etc. by Belcher, Edward, Sir

We have before adverted to the discrepancies in the earth’s compression, as determined by the pendulum, and also to the uncertainty of the moon’s mass, as deduced from the nutation of the earth’s axis.

From Outlines of a Mechanical Theory of Storms Containing the True Law of Lunar Influence by Bassnett, Thomas

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

From Astronomy: The Science of the Heavenly Bodies by Todd, David Peck