precession
/priːˈsɛʃən/
noun
- The slow, circular change in the direction of a spinning object's axis, like the wobble of a top.
- The precession of a spinning top is easy to see as it slows down.
- Gyroscopes are used in spacecraft to control precession.
- The scientist explained the precession of the toy gyroscope to the students.
- The slow shift in the orientation of Earth's axis over a very long period, causing the positions of stars to change gradually.
- The precession of Earth's axis takes about 26,000 years to complete one cycle.
- Ancient astronomers noticed the precession of the equinoxes without modern instruments.
- Because of precession, the North Star will not always be Polaris.