# 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: 424
 geomagnetic storm   توفان ِ زمین‌مغناتیسی، ~ زمین‌مغناتی   tufân-e zamin-meqnâtisi, ~ zamin-meqnâtiFr.: orage géomagnétique   A violent disturbance of the Earth's magnetic field, distinct from regular diurnal variations, following a → solar flare or → coronal mass ejection.→ geomagnetic; → storm. geomagnetism   زمین‌مغنات‌مندی   zamin-meqnâtmandiFr.: géomagnetsme   A branch of geophysics concerned with the study of the Earth's → geomagnetic field, including its origin, spatial extent, and variations in time.→ geo-; → magnetism. geometric   هندسی   hendesi (#)Fr.: géométrique   Of or pertaining to geometry or to the principles of geometry.Adj. of → geometry geometric albedo   سپیدای ِ هندسی   sepidâ-ye hendesiFr.: albedo géométrique   A measure of the → reflectivity of a surface, especially of the solar system bodies (planets, satellites or asteroids). It is the ratio of a body's brightness at zero → phase angle to the brightness of a perfectly diffusing disk with the same position and apparent size as the body. Geometric albedo depends on the radiation wavelength. The bolometric geometric albedo refers to reflectivity in all wavelengths. Compare with the → Bond albedo.→ geometric; → albedo. geometric delay   درنگ ِ هندسی   derang-e hendesiFr.: retard géométrique   One of the two factors contributing to → gravitational lensing time delay that arises from the fact that the bent trajectory is longer than the straight one. The other factor is due to the → Shapiro time delay.→ geometric; → delay. geometric horizon   افق ِ هندسی   ofoq-e hendesiFr.: horizon géométrique   Where the apparent → sea horizon would be if there were no → atmospheric refraction.→ geometric; → horizon. geometric mean   میانگین ِ هندسی   miyângin-e hendesi (#)Fr.: moyenne géométrique   The middle term in a → geometric progression. Of two terms, the geometric mean is the square root of their product. For example, the geometric mean of 4 and 9 is ± 6. For a series of n terms, it is expressed as: (a1.a2. ... .an)1/n.→ geometric; → mean. geometric optics   نوریک ِ هندسی   nurik-e hendesiFr.: optique géométrique   A branch of physics that deals with reflection and refraction of rays of light without reference to the wave or physical nature of light.→ geometric; → optics. geometric progression   فرایازی ِ هندسی   farâyâsi-e hendesi (#)Fr.: progression géométrique   A → sequence in which the ratio of a term to its predecessor is the same for all terms. In general, the nth term has the form ar(n-1), where n is a positive integer, and a and r are nonzero constants; r is called the ratio or common ratio. Also called → geometric sequence.→ geometric; → progression. geometric scattering   پراکنش ِ هندسی   parâkaneš-e hendesiFr.: diffusion géométrique   A type of scattering in which the wavelength (of the light or the sound) is much smaller than the size of object causing the scattering.→ geometric; → scattering. geometric sequence   پی‌آیه‌ی ِ هندسی   peyâye-ye hendesiFr.: suite géométrique   → geometric; → sequence. geometrical libration   رخگرد ِ هندسی   roxgard-e hendesi (#)Fr.: libration géométrique   A lunar libration motion either in latitude resulting from the inclination of the Moon's orbit with respect to the ecliptic, or in longitude due to the elliptical shape of the Moon's orbit which causes a change in its aspect as seen from the Earth. → libration; → physical libration.→ geometric; → libration. geometry   هندسه   hendesé (#)Fr.: géométrie   The branch of mathematics that deals with the nature of space and the size, shape, and other properties of figures as well as the transformations that preserve these properties.From O.Fr. géométrie, from L. geometria, from Gk. geometria "measurement of earth or land," from → geo- + -metria, from metrein "to measure," → -metry.Hendesé, Mid.Pers. handâxtan "to measure," Manichean Mid.Pers. hnds- "to measure," Proto-Iranian ham-, → com-, + *das- "to heap, amass;" cf. Ossetic dasun/dast "to heap up;" Arm. loanword dasel "to arrange (a crowd, people)," das "order, arrangement," geophysics   زمین‌فیزیک   zaminfizik (#)Fr.: géophysique   The branch of physics that deals with the Earth and its environment, including meteorology, oceanography, seismology, and geomagnetism.→ geo-; → physics. geopolitics   زمین‌کاراهیک   zamin-kârâhikFr.: géopolitique   The study or the application of the influence of political and economic geography on the politics, national power, foreign policy, etc., of a state (Dictionary.com).→ geo-; → politics. geostationary orbit   مدار ِ زمین‌ایست‌وّر   madâr-e zamin-istvarFr.: orbite géostationnaire   A satellite orbit in the plane of the Earth's equator and 35,880 km above it, at which distance the satellite's period of rotation matches the Earth's and the satellite always remains fixed in the same spot over the Earth.Geostationary, from → geo- + → stationary; → orbit. geostrophic   زمین‌چرخشی   zamincarxešiFr.: géostrophique   Of or pertaining to the force produced by the rotation of the Earth.From Gk. → geo- + Gk. strophe "a turning," from strephein "to turn," from PIE *strebh- "to wind, turn" + → -ic.From zamin-, → geo-, + carxeši, → rotational. geostrophic balance   ترازمندی ِ زمین‌چرخشی   tarâzmandi-ye zamincarxešiFr.: équilibre géostrophique   Meteo.: The balance between the → Coriolis force and the → pressure gradient force. See also → geostrophic flow.→ geostrophic; → balance. geostrophic flow   تچان ِ زمین‌چرخشی   tacân-e zamincarxešiFr.: écoulement géostrophique   Oceanography: A flow resulting from → geostrophic balance. In geostrophic flow water moves along the lines of constant pressure or → isobars. Geostrophic flow is characterized by small → Rossby and → Ekman numbers.→ geostrophic; → flow. geostrophic wind   باد ِ زمین‌چرخشی   bâd-e zamincarxešiFr.: vent géostrophique   Meteo.: A wind which is balanced by the → Coriolis effect and → pressure gradient force. An air parcel initially at rest will move from high pressure to low pressure because of the pressure gradient force. However, the air parcel in its movement is deflected by the Coriolis force, to the right in the northern hemisphere and to the left on the southern hemisphere. As the wind gains speed, the deflection increases until the Coriolis force equals the pressure gradient force. At this point, the wind will be blowing parallel to the → isobars.→ geostrophic; → wind.