- 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
Examples from the Web for precessional
Historical Examples of precessional
We know the rate at which the earth is spinning, and we have observed the precessional motion.Spinning Tops
The effect of its fluctuation is inseparable from the precessional effect, and is related to it as a modifying condition.
When the eccentricity is large the precessional rhythm is emphasized; when it is small the precessional effect is weak.
The search of the rocks for records of the ticks of the precessional clock is an out-of-door work.
But the precessional motion pulses steadily on through the ages, like the swing of a frictionless pendulum.
Word Origin for precession
1590s, from Late Latin praecissionem (nominative praecissio) "a coming before," from past participle stem of Latin praecedere "to go before" (see precede). Originally used in reference to calculations of the equinoxes, which come slightly earlier each year.