名詞 nutation:

1. uncontrolled nodding

nu.ta.tion

n.（名詞）
The act or an instance of nodding the head.
點頭：點頭的動作或事例
A wobble in a spinning gyroscope or other rotating body.
轉(zhuǎn)動：旋轉(zhuǎn)回轉(zhuǎn)儀或其他轉(zhuǎn)動物體的轉(zhuǎn)動
Astronomy A small periodic motion of the celestial pole of Earth with respect to the pole of the ecliptic.
【天文學】 章動：地球天極就黃道極而言的小的周期性轉(zhuǎn)動
Botany A slight curving or circular movement in a stem, as of a twining plant, caused by irregular growth rates of different parts.
【植物學】 轉(zhuǎn)頭運動：植物莖的輕微彎曲或扭轉(zhuǎn)的生長，象雙生樹那樣，由不同部分的不規(guī)則生長速度引起

來源：
Latin nôt3tiô nôt3tiôn-
拉丁語 nôt3tiô nôt3tiôn-
from nôt3tus [past participle of] nôt3re [frequentative of] -nuere [to nod]
源自 nôt3tus [] nôt3re的過去分詞 [] -nuere的重復動詞 [點頭]

【引伸】
nuta.tional
adj.（形容詞）