An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -le Lag lam Lan Lar las law lea lem lep Li- lig lim lin lin lio lit loc lod lon Lor low Lum lun Lup Lyn > >>

Number of Results: 506
  ۱) شکوه؛ ۲) شکویدن   
1) šekvé (#); šekvidan

Fr.: 1) lamentation, grief; 2) se lamenter   

1a) A real or imagined cause for → complaint, especially unfair treatment.
1b) A feeling of resentment over something believed to be wrong or unfair.
2) To feel or express sorrow or regret for; to mourn for or over (

M.E., from M.Fr. lament and directly from L. lamentum "a wailing, moaning, weeping" from lamentum "a wailing," from PIE root *la- "to shout, cry."

Šekvé, Pers. construction from Ar. šakvâ "complaint."

varaqé (#)

Fr.: lame, lamina   

A thin plate, layer, or flake.

From L. lamina "thin plate or layer, leaf."

Varaqé "sheet, plate," from varaq "a leaf of tree or of paper," from Ar. waraq, from Pers. barg "leaf" (Tabari, Gilaki valg, balg; Kurd. belg, balk, Semnâni valg); Mid.Pers. warg "leaf;" Av. varəka- "leaf;" cf. Skt. valká- "bark, bast, rind;" Russ. volokno "fibre, fine combed flax."


Fr.: laminaire   

Composed of, or arranged in, laminae, sheets.

lamina + → -ar.

laminar boundary layer
  لایه‌ی ِ کرانی ِ ورقه‌ای   
lâye-ye karâni-ye varaqe-yi

Fr.: Couche limite laminaire   

In a fluid flow, layer next to a fixed boundary. The fluid velocity is zero at the boundary but the molecular viscous stress is large because the velocity gradient normal to the wall is large. → turbulent boundary layer.

laminar; → boundary; → layer.

laminar flow
  تچان ِ ورقه‌ای   
tacân-e varaqe-yi

Fr.: écoulement laminaire   

A flow in which the particles of fluid are moving orderly, and in which adjacent layers or laminas glide smoothly over another with little mixing between them. A laminar flow may rapidly transform into a → turbulent flow for large → Reynolds numbers.

laminar; → flow.

laminar sublayer
  زیرلایه‌ی ِ ورقه‌ای   
zirlâye-ye varaqe-yi

Fr.: sous-couche laminaire   

A layer in which the fluid undergoes smooth, nonturbulent flow. It is found between any surface and a turbulent layer above.

laminar; sublayer, from → sub- + → layer.

  لامپ، چراغ   
lâmp (#), cerâq (#)

Fr.: lampe   

Any of various devices producing artificial light, as by electricity, gas, or oil.

From O.Fr. lampe, from L. lampas, from Gk. lampas "torch, lamp, beacon, meteor, light," from lampein "to shine," from PIE base *lap- "to shine" (cf. Lith. lope "light," O.Ir. lassar "flame").

Lâmp, loanword from Fr., as above.
Cerâq "lamp" (variants Kurd. cira, cerâh, Laki cerâx, Zâzâ cərâ, cərâx "lamp, candle," Shughni cirow, cirâw, cərêγ "candle, lamp"); Mid.Pers. cirâq "lamp," related to foruq "light," afruxtan "to light, kindle," rowšan "bright, clear," rowzan "window, aperture;" ruz "day;" Mid.Pers. rôšn "light; bright, luminous," rôc "day;" O.Pers. raucah-rocânak "window;" O.Pers. raocah- "light, luminous; daylight;" Av. raocana- "bright, shining, radiant;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lux "light" (also lumen, luna); Fr. lumière; E. light; O.E. leoht, leht, from W.Gmc. *leukhtam (cf. O.Fris. liacht, M.Du. lucht, Ger. Licht), from PIE *leuk- "light, brightness."

  خشکی، زمین   
xoški (#), zamin (#)

Fr.: terre   

Any part of the earth's surface not covered by a body of water.

M.E., from O.E. land, lond, "ground, soil, territory;" PIE base *lendh- "land, heath" (cf. O.N., O.Fris. Du., Ger., Goth. land; O.Ir. land; Welsh llan "enclosure, church," Breton lann "heath," source of Fr. lande; O.C.S. ledina "waste land, heath," Czech lada "fallow land").

Xoški, from xošk, → dry, + noun suffix -i; zamin "land, → earth."

land breeze
  نسیم ِ خشکی   
nasim-e xoški (#)

Fr.: brise de terre   

A coastal breeze blowing from land to sea after sunset, caused by the temperature difference when the sea surface is warmer than the adjacent land. The warmer air above the water continues to rise, and cooler air from over the land replaces it, creating a breeze.

Land, → lander; → breeze.

Xoški "land," from xošk "dry;" Mid.Pers. xušk "dry;" O.Pers. uška- "mainland;" Av. huška- "dry;" cf. Skt. śuska- "dry, dried out;" Gk. auos "dry, dried up;" O.E. sēar "dried up, withered;" Lith. sausas "dry, barren."

Landau damping
  میرایی ِ لانداؤ   
mirâyi-ye Landau

Fr.: amortissement de Landau   

The process wherein a → plasma gains energy at the expense of the → Langmuir wave. In the presence of the → Landau resonance, the particles in resonance moving slightly faster than the wave lose energy, while those moving slightly slower will gain energy. Since the Maxwellian distribution is decreasing with velocity, in a Maxwellian plasma, near the Landau resonance, there are more particles at lower velocities than at higher velocities. Also called collisionless damping.

Lev Landau (1908-1968), a prominent Soviet physicist, 1962 Nobel Prize in Physics for his development of a mathematical theory of → superfluidity; → damping.

Landau level
  تراز ِ لانداؤ   
tarâz-e Landau

Fr.: niveau de Landau   

The → energy level which can be occupied by a → free electron in a → magnetic field.

Landau damping; → level.

Landau resonance
  باز‌آوایی ِ لانداؤ   
bâzâvâyi-ye Landau

Fr.: résonance de Landau   

For parallel propagating → electrostatic waves in a → plasma, the → resonance which occurs when the particle velocity equals the parallel phase velocity of the wave.

Landau damping; → damping.

Landé factor
  کروند ِ لانده   
karvand-e Landé

Fr.: facteur de Landé   

The constant of proportionality relating the separations of lines of successive pairs of adjacent components of the levels of a spectral multiplet to the larger of the two J-values for the respective pairs. The interval between two successive components J and J + 1 is proportional to J + 1.

After Alfred Landé (1888-1976), a German-American physicist, known for his contributions to quantum theory; → facteur.


Fr.: atterrisseur   

A → space probe designed to land on a → planet or other solid → celestial body.

land; → -er.

Lane-Emden equation
  هموگش ِ لین-امدن   
hamugeš-e Lane-Emden

Fr.: équation de Lane-Emden   

A second-order nonlinear → differential equation that gives the structure of a → polytrope of index n.

Named after the American astrophysicist Jonathan Homer Lane (1819-1880) and the Swiss astrophysicist Robert Emden (1862-1940); → equation

Langevin equation
  هموگش ِ لانژون   
hamugeš-e Langevin

Fr.: équation de Langevin   

Equation of motion for a weakly ionized cold plasma.

Paul Langevin (1872-1946), French physicist, who developed the theory of magnetic susceptibility of a paramagnetic gas; → equation.

Langmuir wave
  موج ِ لانگموییر   
mowj-e Langmuir

Fr.: onde de Langmuir   

A disturbance of a → plasma in the form of a longitudinal, → electrostatic wave that propagates in the plasma due to variations in the plasma's electron density. More specifically, Langmuir waves are collective oscillations of inhomogeneous bunches of electrons displaced from their natural equilibrium, in which the inertia of the relatively massive ions serves to establish an electrostatic restoring force that tries to bring the electrons back to their equilibrium positions. → Landau damping causes dissipation of Langmuir waves as the electrons are either accelerated or decelerated so as to be in resonance with the phase velocity of the waves themselves.

Irving Langmuir (1881-1957), American chemist and physicist, Nobel Prize in Chemistry 1932; → wave.

Langmuir-Hinshelwood mechanism
  ساز-و-کار ِ لنگموییر-هینشلوود   
sâzokâr-e Langmuir-Hinshelwood

Fr.: mécanisme de Langmuir-Hinshelwood   

Suggested by Irving Langmuir (1881-1957) in 1921, who was awarded the Nobel Prize in Chemistry in 1932 for his work in surface chemistry. And further developed by Cyril Hinshelwood (1897-1967) in 1926, who received the Nobel Prize in Chemistry in 1956 for his researches into the mechanism of chemical reactions.

zabân (#)

Fr.: langue   

Any means of conveying or communicating ideas; specifically, human speech.

M.E., from O.Fr. langage, from L. lingua "tongue; speech, language."

Zabân "tongue; language," from Mid.Pers. uzwân "tongue; language;" O.Pers. hzanm, hizânam "tongue," Av. hizuua-, hizū- "tongue;" cf. Skt. jivhā- "tongue;" L. lingua "tongue, speech, language;" O.Ir. tenge; Welsh tafod; Lith. liezuvis; O.C.S. jezyku; M.Du. tonghe; Du. tong; O.H.G. zunga; Ger. Zunge; Goth. tuggo; PIE base *dnghwa-.

language paleontology
  پارین‌شناسی ِ زبانی   
pârinšenâsi-ye zabâni

Fr.: paléontologie linguistique   

An approach in which terms reconstructed in the → proto-language are used to make inferences about its speakers' culture and environment.

language;→ paleontology.

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