What does nutation mean?
Nutation is a specialized word for a small, irregular movement within a larger, more regular motion. In astronomy, it describes the slight nodding or oscillation of a rotating body's axis, superimposed on the slower movement called precession. For Earth, nutation changes the way the axis is oriented and must be included in precise calculations of celestial positions and the apparent motion of the stars. The word also has a botanical use for the spontaneous bending or nodding of a plant organ, particularly a shoot or stem. Although most people may encounter it only in astronomy, nutation illustrates how technical vocabulary can name a subtle but scientifically important feature of motion. It is pronounced with stress on the second syllable and derives from a Latin word associated with nodding.
nounNutation is the small, irregular oscillation of a rotating body's axis superimposed on its steady precession. In biology, it refers to the spontaneous bending or nodding movement of certain plant organs.
- The oscillatory motion of a rotating body's axis, especially the small component of the Earth's motion superimposed on precession.
- The spontaneous nodding or bending movement of a plant organ, especially around the base of a stem.
"Astronomers account for nutation when making highly precise measurements of the Earth's rotation."
"The apparent motion of the stars is influenced by both precession and nutation."
"The young shoot displayed a slow nutation as it grew toward the light."
The plural is used when referring to distinct oscillatory motions or individual instances of nutation.
"The model includes the Earth's nutations over several centuries."
The Earth's axis does not trace a perfectly smooth circle around the celestial pole: its tiny, irregular wobble is called nutation, after the Latin word for nodding.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does nutation come from?
The word comes from Latin nūtātiō, meaning a nodding, and ultimately from nūtāre, “to nod.” English borrowed the term in the context of astronomy, where the small oscillation of a rotating axis resembles a nodding motion. Related English forms include nutate, meaning to nod or move with a slight oscillation, and nutational, describing such movement.
Related word forms
How nutation is actually used
In astronomy, the term is technical and normally refers to a periodic variation in the orientation of a body's axis. Its botanical use is much less common and may sound formal or literary.
Easily confused with nutation
Nutate is a verb meaning to nod or undergo a nodding or oscillatory movement, whereas nutation is the noun naming that movement.