# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 11 Search : axial
 axial   آسه‌ای   âse-yi (#)Fr.: axial   Of, pertaining to, characterized by, or forming an axis.→ axis; → -al. axial inclination   درکیل ِ آسه   darkil-e âséFr.: inclinaison de l'axe   The angle at which a planet's axis of rotation is tilted, with respect to that of the planet's orbit.→ axial; → inclination. axial precession   پیشایان ِ آسه‌ای   pišâyân-e âse-yiFr.: précession axiale   1) A change in the orientation of the → rotation axis of a non-spherical, spinning body caused by → gravity. A rotating top will precess in a direction determined by the → torque exerted by its → weight. The precession → angular velocity is inversely proportional to the spin angular velocity, so that the precession is faster and more pronounced as the top slows down. 2) In particular, the gradual shift in the orientation of Earth's rotation axis which traces out a conical path once every ~ 26,000 years. The cause of the Earth's precession is the → equatorial bulge of the Earth, brought about by the → centrifugal force of the → rotation, which has changed the Earth from a perfect sphere to a slightly flattened one, thicker across the equator. The attraction of the Moon and Sun on the bulge is the reason which makes the Earth precess.→ axial; → precession. axial symmetry   همامونی ِ آسه‌ای   hamâmuni-ye âse-yiFr.: symmétrie axiale   A symmetry with respect to a line. A geometric configuration is said to have axial symmetry if it remains unchanged when rotated about a given line.→ axial; → symmetry. axial tilt   گرای ِ آسه   gerâ-ye âséFr.: inclinaison de l'axe   The angle between an object's → rotation axis and its → orbital axis. In other words, the angle between its → equatorial plane and → orbital plane. Same as → axial inclination and → obliquity, but not to be confounded with → orbital inclination.→ axial; → tilt. biaxial crystal   بلور ِ دو‌آسه   bolur-e doâséFr.: cristal biaxe   A birefrigent crystal, such as mica, that is characterized by having two optical axes along which light is propagated with equal velocities.Biaxial, from → bi- "two" + axial, from → axe; → crystal. equiaxial   هموگ-آسه   hamug-âséFr.: équiaxe   Math.: having three axes of the same length. Also equiaxed. Physics: A crystal exhibiting similar dimensions in all directions.→ equi-; → axis. paraxial   پر‌آسه‌ای   parâse-yiFr.: paraxial   Characteristic of optical analyses that are limited to infinitesimally small apertures. Also called first-order or Gaussian optics.→ para-; → axial.From par(â)-, → para-, + âseyi→ axial. paraxial ray   پرتو ِ پر‌آسه‌ای   partow-e parâse-yiFr.: rayon paraxial   A ray that lies close to and almost parallel to the optical axis and behaves according to paraxial equations.→ paraxial, → ray. solar axial tilt   گرای ِ آسه‌ی ِ خورشید   gerâ-ye âse-ye xoršidFr.: inclinaison de l'axe du Soleil   The angle between the Sun's → rotation axis and perpendicular to the → ecliptic plane. In other words, the inclination of the Sun's → equator with respect to the → ecliptic plane. It is 7.25 degrees.→ solar; → axial; → tilt. uniaxial crystal   بلور ِ یک‌آسه   bolur-e yek-âséFr.: cristal uniaxe   Crystal with double refraction possessing only one → optic axis.→ uni-; axial adj. from → axis; → crystal.