An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1286

Fr.: espèce   

1) A class of individuals having some common characteristics or qualities; distinct sort or kind.
2) Biology: The major subdivision of a genus or subgenus, regarded as the basic category of biological classification, composed of related individuals that resemble one another, are able to breed among themselves, but are not able to breed with members of another species.
3) Logic: One of the classes of things included with other classes in a genus. The set of things within one of these classes (

From L. species "a particular sort, kind, or type," originally "a sight, look, view, appearance," from specere "to look at, to see, behold;" PIE root spek- "to look around," → scope.

Âraz, from intensive/nuance â- + raz-, from Av. razan "order, → rule," from rāz- "to put in line, direct set," cf. Mod.Pers. raj "line, row," variants raž, rak, râk, rezg (Lori), radé, râdé "line, rule, row," rasté, râsté "row, a market with regular ranges of shops;" ris, risé "straight;" → right.


Fr.: précis, explicite, spécifique   

1) Clearly defined or identified; precise; particular.
2) Belonging or relating uniquely to a particular subject; not general.
3) Biology: Relating to species or a species.
4) Physics: Of or denoting a physical quantity expressed in terms of a unit mass, volume, or other measure, in order to give a value independent of the properties or scale of the particular system studied. → specific angular momentum; → specific charge; → specific density; → specific gravity; → specific heat; → specific humidity; → specific intensity; → specific volume.

From Fr. spécifique and directly from L.L. specificus "constituting a kind or sort," from L. species "kind, sort," → species.

Âbizé, from Mid.Pers. apēcak "pure, sacred" (older form of vižé, → special), from *apa-vēcak "set apart," from prefix apa- + vēcak, from vēxtan (Mod.Pers. bixtan) "to detach, separate, sift, remove," Av. vaēk- "to select, sort out, sift," pr. vaēca-, Skt. vic-, vinakti "to sift, winnow, separate; to inquire."

specific angular momentum
  جنباک ِ زاویه‌ای ِ آبیزه   
jonbâk-e zâvie-yi-ye âbizé

Fr.: moment angulaire spécifique   

Angular momentum per unit mass.

specific; → angular; → momentum.

specific charge
  بار ِ آبیزه   
bâr-e âbizé

Fr.: charge spécifique   

The electric charge to mass ratio of an elementary particle.

specific; → charge.

specific density
  چگالی ِ آبیزه   
cagâli-ye âbizé

Fr.: densité spécifique   

Same as → relative density.

specific; → density.

specific gravity
  گرانی ِ آبیزه   
gerâni-ye âbizé

Fr.: gravité spécifique   

The ratio of the density of a substance at the temperature under consideration to the density of water at the temperature of its maximum density (4 °C).

specific; → gravity.

specific heat
  گرمای ِ آبیزه   
garmâ-ye âbizé

Fr.: chaleur spécifique   

1) The quantity of heat required to raise the temperature of 1 gm of a substance through 1 °C. More generally, the → heat capacity of a unit mass of a substance. For a homogeneous body it is expressed as: C = dQ/M dT, where dQ is the quantity of heat transferred to a mass of M to raise the temperature by dT. It is often convenient to use the gram-mole as a unit of mass, → molar heat capacity.
2) For a gas there are two principal specific heats depending on the way in which the temperature is increased: i) that measured at constant pressure, CP, and ii) that measured at constant volume, CV. The specific heat CP is greater than CV, because a gas heated at constant pressure expands, and heat energy must be supplied equivalent to the work done in the expansion. The ratio γ = CP/CV is called the → adiabatic index. It varies from 1.66 for mono-atomic gases to a little over 1 for gases with complex molecules.

specific; → heat.

specific humidity
  نم ِ آبیزه   
nam-e âbizé

Fr.: humidité spécifique   

The dimensionless ratio of the mass of water vapor to the total mass in a particular volume. → humidity

specific; → humidity.

specific intensity
  درتنویی ِ آبیزه   
dartanuyi-e âbizé

Fr.: intensité spécifique   

A measure of the amount of radiation received per unit solid angle per unit time per unit area normally from an element of surface.

specific; → intensity.

specific volume
  گنج ِ آبیزه   
gonj-e âbizé

Fr.: volume spécifique   

The volume occupied by unit mass of a substance. Specific volume is the reciprocal of density.

specific; → volume.


Fr.: précision, spécification   

1) The act of specifying.
2) A particular item, aspect, calculation, etc., in such a description.
3) Something specified, as in a bill of particulars; a specified particular, item, or article (

Verbal noun of → specify.


Fr.: spécifité   

The state or character of being → specific.

specific; → -ity.

  ۱) پرسونیدن؛ ۲) آبیزیدن   
1) parsunidan; 2) âbizidan

Fr.: préciser, spécifier   

1) To mention or name specifically or definitely; state in detail.
2) To give a specific character to; to set forth as a specification (

specific; → -fy.

nemuné (#)

Fr.: specimen   

A part or an individual taken as exemplifying a whole mass or number; a typical animal, plant, mineral, part, etc. → sample.

From L. specimen "mark, example, indication, sign, evidence," from speci- stem of specere "to look at," → -scope, + -men noun suffix denoting result or means.

Nemuné, from nemudan "to show;" Mid.Pers. nimūdan, nimây- "to show," from O.Pers./Av. ni- "down; in, into," → ni- (PIE), + māy- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum; PIE base *me- "to measure."


Fr.: tavelure   

1) Optics: An image defect, one of a large number of bright and dark spots, that appears when an object is illuminated by monochromatic, highly → coherent light. This phenomenon results from the → interference of a number of randomly phased complex contributions of electromagnetic → wavefronts scattered from an object with rough structure, such as a piece of paper, a display screen, or a metallic surface. In particular, whenever the object is rough on the scale of an optical wavelength, the image has a grainy appearance. Also called speckle noise.
2) Astro.: The pattern produced by a short-exposure image of a → point source, such as a star, when the → wavefront is torn apart under the effect of the → atmospheric turbulence. Speckles change very rapidly with time as a function of the atmospheric turbulence. → speckle lifetime. Long exposure images of these changing speckle patterns result in a blurred image of the star, called a → seeing disk. → Fried parameter.

Speckle "a speck or small spot, as a natural dot of color on skin, plumage, or foliage," from M.E.speck (from O.E. specca "small spot, stain," of unknown origin; probably related to Du. speckel "speck, speckle") + -le a noun suffix having originally a diminutive meaning.

Pakâl, from pak "spot" (Lâri, Gerâši), pašy "mingled, confused" (Tâleši), probably related to pisé "dappled, variegated," pis, pisi "leprosy," neveštan "to write," pišé "profession," → professional astronomer; Mid.Pers. parš "speckled, spotted," pēsīdan "to color, adorn," pēsit "adorned;" O.Pers. pais- "to adorn, cut, engrave;" Av. paēs- "to paint, adorn," paēsa- "adornment;" cf. Skt. peś- "to adorn, hew out, decorate," piśáti "adorns; cuts;" Gk. poikilos "multicolored;" L. pingit "embroiders, paints;" O.C.S. pisati "to write;" O.H.G. fēh "multicolored;" Lith. piēšti "to draw, adorn;" PIE base *peik- "colored, speckled."

speckle interferometry
  اندرزنش‌سنجی ِ پَکال   
andarzaneš-sanji-ye pakâl

Fr.: interférométrie des tavelures   

A technique for generating a clear composite image of a celestial object blurred by → atmospheric turbulence in which a large number of short-exposure photographs are mathematically correlated by a computer. By comparing the behavior of the → speckles in a series of images it is possible to approach the theoretical resolution of the telescope.

speckle; → interferometry.

speckle lifetime
  عمر ِ پَکال   
omr-e pakâl

Fr.: durée de vie de tavelures   

The time scale on which a stellar image changes significantly due to → atmospheric turbulence. It is proportional to the ratio r0/Δv, where r0 is the → Fried parameter and Δv the standard deviation of the distribution of wind velocities weighted by the turbulence structure coefficient. Typical lifetimes in the visible range from about 3 to 30 milliseconds.

speckle; → life; → time.

Omr "life-time;" from Ar. 'umr; pakâl, → speckle.

speckle noise
  نوفه‌ی ِ پکال   
nufe-ye pakâl

Fr.: bruit de tavelures   

An image defect associated with the → speckle phenomenon.

speckle; → noise.

binâbi (#)

Fr.: spectral   

Of or pertaining to a → spectrum.

spectrum; → -al.

spectral classification
  رده‌بندی ِ بینابی   
radebandi-ye binâbi (#)

Fr.: classification spectrale   

A system that assigns a → spectral type to a star according to characteristics of its spectrum. The earliest attempt to divide stars on the basis of their spectra was the → Secchi classification in the 1860s. This scheme paved the way for the → Harvard classification that led to the current → Morgan-Keenan classification of spectral types. In the Harvard system stars were originally thought to follow an evolutionary sequence from the "early" O and B types to the "late" K and M types. Although this is now known to be wrong, the terms → early-type star and → late-type star are still in use. In the Morgan-Keenan system stars are classified as type O, B, A, F, G, K, or M in order of decreasing → effective temperature, and each type further subdivided into subclasses from 0 (hottest, except for → O-type stars) to 9 (coolest). They are also accompanied by a → luminosity class. In the late 1990s, spectral types L and T were added to the sequence to accommodate the coolest stars and → brown dwarfs (with class Y reserved for the coolest brown dwarfs of all, as yet unobserved).

spectral; → classification.

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