What does nutational mean?
Nutational is an adjective describing nutation: a small, periodic, nodding or oscillatory movement about an axis. The best-known example is Earth's nutation, the slight wobble in the orientation of its rotational axis caused by the gravitational influence of the Moon and Sun. Nutational motion can also occur in gyroscopes, spacecraft, and other mechanically rotating systems. The word is principally used in astronomy, geophysics, physics, and engineering, where distinguishing a small oscillatory movement from a body's broader rotation is important. In everyday language, one would usually say that something is “wobbling,” “nodding,” or “oscillating” rather than using this specialized term.
adjectiveRelating to nutation, especially the small periodic nodding or oscillatory motion of a body about an axis.
- Relating to or involving the small periodic nodding or oscillatory motion of a body about an axis.
"Earth's nutational motion causes its rotational axis to trace a small, irregular path around the celestial pole."
"The instrument must correct for Earth's nutational movement when tracking a distant radio source."
"Laboratory tests measured the nutational response of the spacecraft to changes in torque."
Earth's axis is not perfectly steady: the Moon and Sun make it gently nod in a motion called nutation.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does nutational come from?
Nutational was formed from the noun nutation with the suffix -al, meaning “relating to.” Nutation comes through Latin nūtātiō, a noun meaning “a nodding” derived from nūtāre, “to nod or sway,” which is associated with Latin nōdus, “knot.” The same Latin root underlies the English words node and nodal, as well as the verb nutate.
Related word forms
How nutational is actually used
This is a technical term used chiefly in astronomy, geophysics, physics, and mechanical engineering. It is uncommon in general prose.
Easily confused with nutational
Nutation is the noun naming the nodding or oscillatory motion, while nutational is the adjective describing it.