To nutate generally means to “rock, sway, or nod; usually involuntarily”. It comes from Latin nutare, meaning “to nod repeatedly”. But the noun nutation has several specific meanings:
- "an act or instance of nodding one's head, esp. involuntarily or spasmodically"
- "a wobble in a spinning gyroscope or other rotating body"
- "a slight curving or circular movement in a stem, as of a twining plant, caused by irregular growth rates of different parts."
- "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)"
As you can see, it’s quite a scientific word. I learned it from Late Night with Conan O’Brien, in an episode where MIT Physics Professor Peter Fisher helped Conan beat his ring-spinning record. (Read about it on the MIT blog.) Professor Fisher defined nutate as “to get floppy”, which isn’t entirely accurate, but it made a much better set-up for Conan’s silly double entendre. :roll: