An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 699

Fr.: redondance   

The fact of repeating or duplicity.
That part of the data content that can be dropped without any significant loss of the original information.

From L. redundantia "an overflowing, excess," from redundare "to flow back, overflow, be excessive," from → re- "again" + undare "rise in waves," from unda "a wave."

Afzun-âyi "redundancy, superabounding," from afzun "more, greater; more ample," from afzudan "to add, increase" (Mid.Pers. abzudan "to increase, grow;" O.Pers. abijav- "to increase, add to, promote," from abi-, aiby- "in addition to; to; against" + root jav- "press forward;" Av. gav- "to hasten, drive;" Sk. jav- "to press forward, impel quickly, excite," javate "hastens") + âyi verbal noun of ây- present stem of âmadan "to come, arrive, become" (Av. ay- "to go, to come," aēiti "goes;" O.Pers. aitiy "goes;" Skt. e- "to come near," eti "arrival;" L. ire "to go;" Goth. iddja "went," Lith. eiti "to go;" Rus. idti "to go").

bâzbordan (#)

Fr.: référer   

1) To direct for information or anything required.
2) To hand over or submit for information, consideration, decision, etc.
3) To have relation; relate.
4) To make reference or allusion (

M.E. referren, from L. referre "to bring back," from → re- "back" + ferre "carry, bear," cognate with Pers. bordan "to carry, bear," as below.

Bâzbordan, literally "to bring back," from bâz "back," → re- + bordan "to carry, bear" (Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry;" PIE base *bher- "to carry").

bâzbord (#)

Fr.: référence   

1) An act or instance of referring.
2) A book, article, or passage to which one is directed.

Verbal noun of → refer.

reference ellipsoid
  بیضی‌وار ِ بازبرد   
beyzivâr-e bâzbord

Fr.: ellipsoïde de référence   

A mathematically defined surface that approximates the Earth's shape, which is basically a sphere "flattened" at its poles. The length of one of the axes at the Equator is chosen so that the ellipsoid coincides at this latitude with the mean sea level. It is the first-order definition of the non-spherical shape of the Earth as an ellipsoid of revolution. To first order, it accounts for over 90% of the → geoid.

reference; → ellipsoid.

reference frame
  چارچوب ِ بازبرد   
cârcub-e bâzbord

Fr.: système de référence   

A set of axes to which positions and motions in a system can be referred. Same as → frame of reference.

reference; → frame.

reference source
  خن ِ بازبرد   
xan-e bâzbord

Fr.: source de référence   

An astronomical source in a field used as a reference for the detection of another object, astrometry, etc.

reference; → source.

  ۱) نازکیدن؛ ۲) نازکیدن   
1) pâludan; 2) nâzokidan

Fr.: raffiner   

1) To bring to a fine or a pure state; free from impurities.
2) To make more fine, subtle, or precise (

re-; → fine.

1) Pâludan "to purify, starin, → filter."
2) Nâzokidan, from nâzok "tender, delicate, subtle, neat," → fine.

  ۱) پالایش؛ ۲) نازکش   
1) pâlâyeš; 2) nâzokeš

Fr.: raffinement   

1) Fineness or elegance of feeling, taste, manners, language, etc.
2) The act or process of refining. the quality or state of being refined.
3) An improved, higher, or extreme form of something.
Math.: A → set whose elements include the elements of a given set (

Verbal noun of → refine.



Any of a series of features occurring in the → light curve of → dwarf novae and → Soft X-ray Transient (SXT)s during → outburst decay. Reflares appear when the surface density Σ behind the cooling front is high enough to reach Σmax. At the radius at which this happens, the disk becomes thermally unstable and a new heating front develops. This front propagates outward like an inside-out outburst, reheating the disk until Σ(R) ≤ Σmin, when cooling can resume. The density in the cold region is depleted as matter is accreted during this process, and the following reflare occurs at smaller radii and have lower amplitudes (G. Dubus et al., 2001, A&A 373, 251).

re-; → flare.

bâztâbidan (#)

Fr.: réfléchir   

To throw or bend back from a surface, specially light, sound, or heat.

M.E. reflecten, from L. reflectere "to bend back," from → re- "back" + flectere "to bend."

Bâztâbidan, from bâz-, → re- + tâbidan, variants tâftan "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "; to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."


Fr.: réflectance   

1) Same as → reflection factor.
2) Computers: In optical character recognition, the relative value of the ink color compared to the background.

From → reflect + -ance

Bâztâbâyi, verbal noun from adj./agent noun bâztâbâ "reflecting."

reflected ray
  پرتو ِ بازتابیده   
partow-e bâztâbidé (#)

Fr.: rayon réfléchi   

A → light ray that is reflected from a surface.

reflect; → ray.

reflecting circle
  دایره‌ی ِ بازتابی   
dâyere-ye bâztâbi

Fr.: cercle à réflexion   

An instrument for measuring angular distances, based on the same principle as the → octant, but with a full circular limb divided into 720°. It was invented in 1752 by the German astronomer Johann Tobias Mayer (1723-1762) to improve on the octant which often gave wrong results because of incorrect graduations. The instrument consisted of an index arm and a small telescope, both pivoted centrally. In practice, the index arm is first set to zero, and the telescope rotated until the two images of a star are seen in coincidence (the one directly, the other by double reflection). Then the index arm is freed, and rotated until the other object is seen in coincidence after double reflection. The angle has now been measured, but the double operation is repeated several times, and the final angle divided by the number of repetitions to find a mean value. Hence, the instrument was sometimes called a "repeating circle." The reflecting circle had little success because it was heavy and uncomfortable to use. Its improved form is called → Borda circle.

reflection; → circle.

reflecting telescope
  تلسکوپ ِ بازتابی، دوربین ِ ~   
teleskop-e bâztâbi (#), durbin-e ~ (#)

Fr.: télescope réflecteur   

A telescope in which the image is produced by reflection of light by a concave mirror.

Reflecting, verbal adj. of → reflect; → telescope.

bâztâb (#)

Fr.: réflexion   

The return of radiation after striking a surface, without change in wavelength. If the surface is smooth, reflection is regular, otherwise it is diffuse. → diffuse reflection; → specular reflection.

Verbal noun of → reflect.

reflection coefficient
  همگر ِ بازتاب   
hamgar-e bâztâb (#)

Fr.: coefficient de réflexion   

The ratio given by the → amplitude (or energy) of a reflected wave divided by the amplitude (or energy) of the incident wave.

reflection; → coefficient.

reflection factor
  کروند ِ بازتاب   
karvand-e bâztâb

Fr.: facteur de réflexion   

The ratio of total flux that is reflected from a surface to the incident flux. Also called reflectance, reflectivity.

reflection; → factor.

reflection nebula
  میغ ِ بازتابی   
miq-e bâztâbi

Fr.: nébuleuse par réflexion   

A type of nebula that is visible from its reflection of starlight. Bright stars near reflection nebulae emit light into the region that is reflected by the large amount of dust there. The size of the dust grains causes blue light to be reflected more efficiently than red light, so these reflection nebulae frequently appear blue in color.

reflection; → nebula.

bâztâbi (#)

Fr.: réfléchissant, réflecteur   

That reflects; reflecting. Of or pertaining to reflection.

From → reflect + -ive a suffix of adjectives and nouns of adjectival origin.

Bâztâbi adj. of bâztâb, → reflection.


Fr.: réflectivité   

Same as → reflectance; → reflection factor.

From → reflective + → -ity.

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