An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) General: The quality or state of being oblique.
2) The → angle that an object's → rotational axis makes with its → orbital axis. In other words, the angle between its → equatorial plane and → orbital plane. Same as → axial tilt.

State noun of → oblique.

The angle between the Earth's → equatorial plane and the → ecliptic. Its present value is 23°26'13.5'' (or 23.43708 degrees). The effects of → precession and → nutation cause it to change between extreme values of 22.1 and 24.5 degrees over a period of approximately 41,000 years. It is currently decreasing.

→ obliquity; → ecliptic.