nutation

1610s, from Latin nūtātiō (“nodding”), from nūtō (“I nod”), from Proto-Indo-European *neu-.[1] Compare mutation.

• Rhymes: -eɪʃən

nutation (countable and uncountable, plural nutations)

1. (physics) A bobbing motion that accompanies the precession of a spinning rigid body.
2. A nodding motion (of the head etc.).
3. (astronomy) Any of several irregularities in the precession of the equinoxes caused by varying torque applied to the Earth by the Sun and the Moon.
4. (botany) The circular motion of the tip of a growing shoot.

• circumnutation
• counternutation
• nutate