An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -fy fac fal Far fed Fer fer fie fin fir fit fla flo flu fol for for Fou fra fre Fre fro fuz > >>

Number of Results: 452
   -ایدن، کردن، ساختن، آردن   
-idan, kardan, sâxtan, ârdan

Fr.: -fier, faire   

Suffix meaning "to make, cause to be."

From Fr. -fier, from L. -ficare, from facere "to make, do;" cognate with Pers. dâdan "to give;" → fact.

Suffix -idan forming infinitives; kardan "to do, to make," → -ize; sâxtan "to build, make, fashion," → perfect; ârdan contraction of âvardan "to bring; to cause, produce" (Mid.Pers. âwurtan, âvaritan; Av. ābar- "to bring; to possess," from prefix ā- + Av./O.Pers. bar- "to bear, carry," bareθre "to bear (infinitive)," bareθri "a female that bears (children), a mother;" Mod.Pers. bordan "to carry;" Skt. bharati "he carries;" Gk. pherein; L. fero "to carry").

F corona
  تاج ِ F   
tâj-e F

Fr.: couronne F   

The exterior part of the → solar corona, illuminated by solar light scattered or reflected by dust particles. The same phenomenon also produces the → zodiacal light, much farther away from the Sun. The dust particles are at most several microns in size and make up a disk stretching over almost 1 solar radius (700,000 km) from the Sun's surface. Unlike electrons, which are responsible for the → K corona, the dust particles move relatively slowly. Thus, the light scattered by them has the same spectrum as the → photosphere and shows the → Fraunhofer lines. The F corona is the most luminous part of the corona at 1.5 solar radii from the Sun's surface (M.S.: SDE).

F referring to the Fraunhofer lines; → corona.

f mode
  ترز ِ f، مُد ِ ~   
tarz-e f, mod-e ~

Fr.: mode f   

Waves that propagate only on the stellar surface. See also: → oscillation mode; → g mode; → p mode.

f referring to → fundamental; → mode.

F ring
  حلقه‌ی ِ F   
halqe-ye F

Fr.: anneau F   

The → Saturn's ring, with a width of 30-500 km, lying just outside of the → A ring, at 140,210 km from the center of Saturn.


f(R) gravity
  گرانی ِ (R)f   
gerâni-ye f(R)

Fr.: gravité f(r)   

An extension of Einstein's → general relativity derived from relaxing the hypothesis that the → Hilbert-Einstein action for the → gravitational field is strictly linear. This was done by replacing the → Ricci scalar, R, with a non-linear function of R:
S = (1/2κ)∫d4x (-g)1/2f(R) + Sm,
where κ ≡ 8πG and Sm is the matter part of the action. The case of f(R) = R represents the simplest type of f(R) gravity theories. The discovery of → dark energy in 1998 stimulated the idea that → cosmic acceleration today may originate from some modification of gravity to general relativity. Dark energy models based on f(R) theories have been extensively studied as the simplest modified gravity scenario to realize the late-time acceleration. There are three versions of f(R) modified gravity: metric (or second order) formalism, Palatini (or first order) formalism, and metric-affine gravity.

f(R), function of the → Ricci scalar; → gravity.

  عدد ِ کانونی   
adad-e kânuni (#)

Fr.: nombre d'ouverture   

Same as → focal ratio.

f, from → focal; → number.

F-type star
  ستاره‌ی ِ گونه‌ی ِ F   
setâre-ye gune-ye F

Fr.: étoile de type F   

A star whose spectrum is characterized by strong → absorption lines of ionized → calcium, Ca II (→ H and K lines), which become much stronger than the hydrogen lines of the → Balmer series. A multitude of fainter metallic lines are also present. Ca II lines strengthen to later types. → Main sequence F stars, of which → Procyon is an example, have a → surface temperature of 6,000 to 7,400°C and a mass of 1.1 to 1.4 → solar masses (Habets & Heintze, 1981, AASS 46, 193).

B, letter of alphabet used in the → Harvard classification; → type; → star.

Faber-Jackson relation
  بازانش فیبر-جکسون   
bâzâneš-e Faber-Jackson

Fr.: relation Faber-Jackson   

An empirical power-law correlation between the luminosity (L) and the velocity dispersion of stars (σ) in the center of a elliptical galaxies. The original relation can be expressed mathematically as: L ∝ σγ, where the index γ is observed to be approximately equal to 4, but depends on the range of galaxy luminosities that is fitted. → Tully-Fisher relation.

After the astronomers Sandra M. Faber and Robert Earl Jackson, who first noted this relation in 1976 (ApJ 204, 668); → relation.

afsâné (#)

Fr.: fable   

1) A short tale to teach a moral lesson, often with animals or inanimate objects as characters.
2) A story not founded on fact.
3) A story about supernatural or extraordinary persons or incidents; legend (

M.E. able, fabel, fabul, from O.Fr. fable "story, fable, tale; drama, play, fiction; lie, falsehood," from L. fabula "story, story with a lesson, tale, narrative, account; the common talk, news," literally "that which is told," from fari "speak, tell," from PIE root *bha- "speak."

Afsâné, from Proto-Ir. *abi-sanhana-, from *sanh- "to declare, explain;" cf. O.Pers. θanh- "to declare, say;" Av. səngh- "to declare;" → speech.

Fabry-Perot interferometer
  اندرزنش‌سنج ِ فابری-پرو   
andarzaneš-sanj-e Fabry-Perot

Fr.: interféromètre Fabry-Pérot   

A type of interferometer wherein the beam of light undergoes multiple reflections between two closely spaced partially silvered surfaces. Part of the light is transmitted each time the light reaches the second surface, resulting in multiple offset beams which can interfere with each other. The large number of interfering rays produces an interferometer with extremely high resolution, somewhat like the multiple slits of a diffraction grating increase its resolution.

The design was conceived by French physicists Charles Fabry (1867-1945) and Alfred Pérot (1863-1925) in the late nineteenth century; → interferometer.

afsâné-bâftan (#)

Fr.: affabuler, inventer   

1) To tell invented stories; create fables or stories filled with fantasy.
2) To relate an event as a fable.

From L. fabulatus perfect passive participle of fabulor, from fabula, → fable.

Afsâne-bâftan "to forge fables, stories," from afsâné, → fable, + bâftan "to weave, twist, plait," → texture.

afsâné-bâfi (#)

Fr.: fabulation, affabulation   

1) To tell invented stories; create fables or stories filled with fantasy.
2) To relate an event as a fable.

fabulate; → -tion.

  افسانه‌ای، افسانه‌گون   
afsâne-yi, afsânegun

Fr.: fabuleux, extraordinaire, légendaire   

1) Almost impossible to believe; incredible.
2) Exceptionally good or unusual; marvelous; superb.

fable; → -ous.

  دیم، رو، رخ، رخسار   
dim, ru, rox, roxsâr

Fr.: face   

1) The front part of the head, from the forehead to the chin.
2) A plane surface of a geometric solid. The front of something having more than two sides. → interface.

M.E., from O.Fr. face, from L. facies "appearance, form; visage, countenance."

Dim "face," from Av. daēman- "eye," from dā(y)- "to see," didāti "sees" (cf. Mod.Pers. didan "to see," Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").
Ru(y), variant rox "face, surface; aspect; appearance" (Mid.Pers. rôy, rôdh "face;" Av. raoδa- "growth," in plural form "appearance," from raod- "to grow, sprout, shoot;" cf. Skt. róha- "rising, height").

face angle
  زاویه‌ی ِ دیمی، دیم-زاویه   
zâviye-ye dimi, dim-zâviyé


An angle formed by any two adjacent edges of a → polyhedron, in contrast to a → dihedral angle.

face; → angle.

face-on galaxy
  کهکشان ِ رونما   
kahkešân-e runemâ

Fr.: galaxie vue de face   

A → spiral galaxy oriented such that it is viewed from above or below. → edge-on galaxy.

face; → on-; → galaxy.


Fr.: faciliter   

To make easier, render less difficult.

From Fr. faciliter "to make easy," from stem of L. facilis "easy to do," from facere "to do," → fact.

Âsânidan "to render easy," from âsân, → easy.


Fr.: facilitation   

The act or process of facilitating.

facilitate; → -tion.


Fr.: facilité   

1) Ease in moving, acting, or doing.
2) Something that facilitates an action or process.
3) A building, room, array of equipment, or a number of such things, designed to serve a particular function (

facile; → -ity.

Âsânâk, from âsân "easy," + relation suffix -âk, as in xorâk, pušâk, dârâk.

  باشا، بوده   
bâšâ, budé (#)

Fr.: fait   

Something that has actual existence; a piece of information presented as having objective reality. → scientific fact.

L. factum "event, occurrence," literally "something done, deed," from neut. p.p. of facere "to do" (cf. Fr. faire, Sp. hacer), from PIE base *dhe- "to put, to do" (cf. Mod.Pers. dâdan "to give;" O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives; puts;" Skt. dadáti "puts, places;" Hitt. dai- "to place;" Gk. tithenai "to put, set, place;" Lith. deti "to put;" Czech diti, Pol. dziac', Rus. det' "to hide," delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do").

Bâšâ, from bâš + agent suffix; bâš, present stem of budan "to be," from Mid.Pers. budan, from O.Pers./Av. bav- "to be; become, take place;" Av. buta- perf. ptcpl. pass., bavaiti "becomes" (cf. Skt. bhavati "becomes, happens," bhavah "becoming; condition, state;" PIE *bheu- "to be, come into being, become;" Gk. phu- "become," phuein "to bring forth, make grow;" L. fui "I was" (perf. tense of esse), futurus "that is to be, future;" Ger. present first and second person sing. bin, bist; E. to be; Lith. bu'ti "to be;" Rus. byt' "to be"); budé also from budan.

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