- the slow, conical motion of the earth's axis of rotation, caused by the gravitational attraction of the sun and moon, and, to a smaller extent, of the planets, on the equatorial bulge of the earth.
- precession of the equinoxes.
Origin of precession
Related formspre·ces·sion·al, adjective
Examples from the Web for precessional
For instance, the precessional motion of a top cannot be reversed unless we reverse the spin.
The search of the rocks for records of the ticks of the precessional clock is an out-of-door work.
When the eccentricity is large the precessional rhythm is emphasized; when it is small the precessional effect is weak.
So that the precessional motion changes its rate every quarter year from a maximum to nothing, or from nothing to a maximum.
If the precessional velocity is too small, the top will fall, and as it falls the precessional velocity increases.