What is nutation in relation to earth?

The cyclic precession-nutation motion of the polar axis of the Earth

is similar to the motion of thf the spinning toy, Top.

Precession is motion along the surface of a double right circular

cone, with vertex near the center of the Earth. The period of this

revolution is called Great Year = 258 centuries, nearly. The semi-

Tn this interactive play of mutual attractions of the triad the Earth,

the Sun and the Earth's orbiter Luna, there is lateral oscillations

(nodding) of either Pole called Nutation, on the surface of the Earth,

about its Great Year circular path.. This nutation comprises quite a

number of oscillations with different periods.

For graphic depiction see wikipedia.org/wiki/Nutation

The gravitational pull of the Moon and Sun on the Earth's equatorial bulge causes a phenomenon known as nutation, which causes the Earth's axis of rotation to slightly wobble as it rotates. Over time, this causes a small, cyclical movement of the Earth's rotational axis.