- the act of preceding; precedence
- Astron. precession of the equinoxes
- Mech. an effect exhibited by a spinning body, as a top, when an applied torque tends to change the direction of its rotational axis, causing this axis generally to describe a cone and to turn at right angles to the direction of the torque
Origin of precessionMiddle English ; from Late Latin praecessio ; from Classical Latin praecedere, to precede
- The act or state of preceding; precedence.
- Physics The motion of the axis of a spinning body, such as the wobble of a spinning top, when there is an external force acting on the axis.
- Astronomy a. Precession of the equinoxes.b. A slow gyration of the earth's rotational axis around the pole of the ecliptic, caused by the gravitational pull of the sun, moon, and other planets on the earth's equatorial bulge.
Origin of precessionLate Latin praecessi&omacron;, praecessi&omacron;n-, from Latin praecessus, past participle of praec&emacron;dere, to go before; see precede.
(countable and uncountable, plural precessions)
- (uncountable) precedence
- (physics, countable) The wobbling motion of the axis of a spinning body when there is an external force acting on the axis.
- (astronomy, uncountable) The slow gyration of the earth's axis around the pole of the ecliptic, caused mainly by the gravitational torque of the sun and moon.
- Any of several slow changes in an astronomical body's rotational or orbital parameters.