An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 452
flat Universe
  گیتی ِ تخت   
giti-ye taxt

Fr.: univers plat   

A Universe where the → geometry is → Euclidean, i.e. parallel lines remain parallel when extended into the distance and the sum of the interior angles of a triangle is 180°. The → space-time in a flat Universe has a null → curvature constant, k = 0. See also → closed Universe, → open Universe.

flat; → universe.

  میدان ِ تخت   

Fr.: champ plat   

Exposure of a diffuse and uniform source in order to calibrate the non-uniformity of an imaging detector such as a CCD.

flat; → field.

Meydân, → field; taxt, → flat.

flatness problem
  پراسه‌ی ِ تختی   
parâse-ye yaxti

Fr.: problème de la platitude   

The observed fact that the → geometry of the → Universe is very nearly flat, in other words its density is very close to the → critical density. This would be an extreme coincidence because a → flat Universe is a special case. Many attempts have been made to explain the flatness problem, and modern theories now include the idea of → inflation.

flat; → problem.

câšni (#)

Fr.: saveur   

11 Taste, especially the distinctive taste of something as it is experienced in the mouth. A particular quality noticeable in a thing (
2) Any of the six labels given to the distinct kinds of → quark: up, down, strange, charm, bottom, and top.
3) → neutrino flavor.

M.E., from O.Fr. flaor "smell, odor; action of smelling, sense of smell," probably from V.L. flator "odor," literally "that which blows," in L. "blower," from flareQ "to blow, puff," which is cognate with O.E. blawan, → blow.

Câšni "taste; taste by way of a sample; quality," related to cašidan, caš- "to taste," câšt "breakfast," cašté "bait;" Mid.Pers. câšt "meal," câšnig "taste;" cf. Skt. cas- "to eat;" Proto-Ir. caš- "to eat, to drink; to drip."

Fleming's rules
  رزن‌های ِ فلمینگ   
razanhâ-ye Fleming

Fr.: règles de Fleming   

Two rules used to assist in remembering the relative directions of the magnetic field, current, and motion in electrical machines, using one's fingers. The right hand refers to generators, the left hand to motors. The three directions are represented by the thumb (for force or motion), forefinger (for field), and second finger (for current), all held at right angles to each other.

Devised by the British physicist and electrical engineer John Ambrose Fleming (1849-1945).

  چفتیدن، چفتن   
caftidan, caftan


1) To bend or be bent.
2) Of a material, to be capable of warping or bending and then reverting to shape (

Probably a back-formation from → flexible, from L. flexus, p.p. of flectere "to bend, turn."

Caftidan, caftan "to bend, incline," cafté "curved, bent," of unknown origin.


Fr.: flexibilité   

1) The quality of bending easily without breaking.
2) The ability to be easily modified.

flexible; → -ity.


Fr.: flexible   

Capable of being bent easily without breaking.

flex + -ible, variant of → -able.



1) The act of bending, the state of being bent.
2) The position that a limb assumes when it is bent.

flex; → -tion.


Fr.: flexion   

The action of bending or curving, or the condition of being bent or curved.

flex + suffix -ure.

parvâz (#)

Fr.: vol   

The act, manner, or power of flying.

O.E. flyht "a flying, flight," from P.Gmc. *flukhtiz (cf. Ger. Flucht).

Parvâz, from Mid.Pers. parwâz; Av. pāirivāza- "overrunning," from pāiri- "over (of space), from" + vāza- from vaz- "to fly, float; to drive;" cf. Skt. vah-, vahati. Also Mid.Pers. vâz "jump, flight," Mod.Pers. Lori, Gilaki, Tabari vâz "jump, leap."

flint glass
  فلینت، شیشه‌ی ِ ~   
flint, šiše-ye ~ (#)

Fr.: flint, flint-glass   

A basic type of optical glass containing lead oxide and a smaller amount of potassium, characterized by its brilliance, clarity, and durability. It has a high → dispersion relative to its → refractive index, as compared to, e.g. → crown glass. Flint glass is sometimes used as the diverging lens component of an → achromatic lens. It is also used in the manufacture of table glassware.

Flint, because it was originally made of calcined flints, from M.E., O.E.; cf. M.Du. vlint, O.H.G. flins, Dan. flint; Gk. plinthos "brick, tile."

flocculent spiral galaxy
  کهکشان ِ مارپیچ ِ پشمین   
kahkešân-e mârpic-e pašmin

Fr.: galaxie spirale floculente   

A galaxy that has short segments of patchy spiral structure so that the disk appears like the fleece of a sheep. Examples: NGC 2841 and NGC 5055.

From L. floccus "flock of wool" + -ulent; → spiral galaxy.

Kahkešân, → galaxy; mârpic, → spiral; pašmin "woolly, woollen," from pašm "wool" (Mid.Pers. pašm "wool;" Av. pašna- "eyelash, eyelid;" cp. Skt. páksman- "eyelashes;" Gk. pekos "wool, fleece," pek(t)ein "to comb, pluck;" Lith. pešti "to pluck;" O.N. fax "mane").

  لف، سیل   
laf, seyl (#)

Fr.: inondation   

The overflowing of the normal confines of a stream or other body of water, or the accumulation of water over areas that are not normally submerged.

O.E. flod "a flowing of water, river, sea," from P.Gmc. *flothuz (cf. M.Du. vloet, Ger. Flut), from PIE *plo-/*pleu- "flow, float" (cf. Gk. ploein "to float, swim").

Laf "flood," from Lori, Kordi, Malâyeri, in Tabari, variants lur, lây "flood" [Mo'in, Dehxodâ]; cf. Gk. louein "to wash;" L. luere "to wash;" Bret. laouer "trough;" PIE *lou- "to wash." Seyl from Ar.

kaf (#)

Fr.: sol   

1) That part of a room, hallway, or the like, that forms its lower enclosing surface and upon which one walks.
2) A level, supporting surface in any structure (

M.E. flor, from O.E. flor (cf. M.Du. vloer, M.H.G. vluor, Ger. Flur "field, meadow"), from PIE *plaros, from *pele- "flat; to spread."

Kaf "floor; plain ground."

Flora family
  خانواده‌ی ِ فلورا   
xânevâde-ye Flora

Fr.: famille Flora   

An → asteroid family that includes → Gaspra. The group has about 819 members and orbits between 2.17 and 2.33 → astronomical units from the Sun.

Flora; → family.

šenâvari (#)

Fr.: flottation   

1) The act or state of remaining on the surface of a liquid. → buoyancy.
2) The process of separating different materials, especially minerals, by agitating a pulverized mixture of the materials with water, oil, and chemicals based on their tendency to sink in, or float on.

From float, from M.E. floten,  O.E. flotian (cf. O.N. flota, M.Du. vloten), akin to fleet + -ation.

Šenâvari "flotation," from šenâvar "that swims, floats," from šenâ "swimming;" Mid.Pers. šnâz "swim," šnâzidan "to swim;" Av. snā- "to wash, swim;" cf. Skt. snā- "to bathe, to wash;" L. nare, natare "to swim" (Fr. nage, nager, natation; Sp.nadar, natacion).

  ۱) تچان؛ ۲) تچیدن   
1) tacân; 2) tacidan

Fr.: 1) flot, écoulement; 2) couler, s'écouler   

1a) Moving along in a → stream; going as in a stream.
1b) A → dynamical system that evolves continuously with time.
1c) The transference of energy.
2) The corresponding verb.

O.E. flowan, from P.Gmc. *flo- (cf. Du. vloeien "to flow," O.H.G. flouwen "to rinse, wash"), probably from PIE *pleu- "to flow, float" (cf. Skt. plavate "navigates, swims," plavayati "overflows;" Gk. plyno "I wash," pleo "swim, go by sea;" L. pluere "to rain;" Arm. helum "I pour;" Lith. pilu "to pour out").

1) Tacân, from tac- variant tâz- present stem of tacidan, tâxtan, tâzidan "to run; to hasten; to assault," + noun and adj. suffix -ân. Related to the first component are Mod.Pers. tajan name of a river (initially "flowing, streaming, stream"), tâzi "swift (greyhound)," tak "running, rush," from Mid.Pers. tâz-, tâxtan "to flow, to cause to walk," tc- "to flow, to walk," tag "running, attack," tâzig "swift, fast;" Khotanese ttajs- "to flow, to walk;" Av. tac- "to run, to flow," taciāp- "flowing water," tacinti (3pl.pers.act.) "to flow," tacar- "course," tacan "current, streaming;" cf. Skt. tak- "to rush, to hurry," takti "runs;" O.Ir. tech- "to flow;" Lith. teketi "to walk, to flow;" O.C.S. tešti "to walk, to hurry;" Tokharian B cake "river;" PIE base *tekw- "to run; to flow."
2) Verbal form.

flow line
  خط ِ تچان   
xatt-e tacân

Fr.: ligne d'écoulement   

Same as → streamline.

flow; → line.

flow rate
  نرخ ِ تچان   
nerx-e tacân

Fr.: débit   

The amount of a substance, specifically a → fluid, moving across a specified unit → area in a given amount of → time.

flow; → rate.

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