An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -le Lag lam lan Lar lat law Lea len lep lig lig lin lin lin liq loa Loc log loo low lum lun lun Lym > >>

Number of Results: 490
Leavitt law
  قانون ِ لویت   
qânun-e Leavitt

Fr.: loi de Leavitt   

Same as the → period-luminosity relation.

Named after Henrietta Swan Leavitt (1868-1921), American woman astronomer, who discovered the relation between the luminosity and the period of → Cepheid variables (1912); → law.

Leclanché cell
  پیل ِ لوکلانشه   
pil-e Leclanché (#)

Fr.: pile de Leclanché   

A → primary cell in which the anode is a rod of carbon and the cathode a zinc rod both immersed in an electrolyte of ammonia plus a depolarizer.

Named after the inventor Georges Leclanché (1839-1882), a French chemist, → cell.

Ledâ (#)

Fr.: Léda   

1) The ninth of Jupiter's known satellites and the smallest. It is 16 km in diameter and has its orbit at 11 million km from its planet. Also called Jupiter XIII, it was discovered by Charles Kowal (1940-), an American astronomer, in 1974.
2) An asteroid, 38 Leda, discovered by J. Chacornac in 1856.

In Gk. mythology, Leda was queen of Sparta and the mother, by Zeus in the form of a swan, of Pollux and Helen of Troy.

Ledoux's criterion
  سنجیدار ِ لو‌دو   
sanjidâr-e Ledoux

Fr.: critère de Ledoux   

An improvement of → Schwarzschild's criterion for convective instability, which includes effects of chemical composition of the gas. In the Ledoux criterion the gradient due to different molecular weights is added to the adiabatic temperature gradient.

After the Belgian astrophysicist Paul Ledoux (1914-1988), who studied problems of stellar stability and variable stars. He was awarded the Eddington Medal of the Royal Astronomical Society in 1972 (Ledoux et al. 1961 ApJ 133, 184); → criterion.

cap (#)

Fr.: gauche   

Of, pertaining to, or located on or toward the west when somebody or something is facing north. Opposite of → right.

M.E. left, lift, luft, O.E. left, lyft- "weak, idle," cf. Ger. link, Du. linker "left," from O.H.G. slinc, M.Du. slink "left," Swed. linka "limp," slinka "dangle."

Cap "left," from unknown origin.

left-hand rule
  رزن ِ دست ِ چپ   
razan-e dast-e cap

Fr.: règle de la main gauche   

See → Fleming's rules.

left; → hand; → rule.

  چپال، چپدست   
capâl (#) , capdast (#)

Fr.: gaucher   

Using the left hand with greater ease than the right.

left; → hand + -ed.

Capâl, from cap, → left, + -al, → -al. Capdast, with dast, → hand.

  ۱) لنگ؛ ۲) ساق   
1) leng (#); 2) sâq (#)

Fr.: jambe   

1) The part of the body from the top of the → thigh down to the → foot.
2) Anatomy: The lower limb of a human being between the → knee and the → ankle.

M.E., from O.Norse leggr; cognate with Dan. læg, Swed. läg "the calf of the leg."

Leng, related to Mid.Pers. zang "shank, ankle;" Av. zanga-, zənga- "bone of the leg; ankle bone; ankle;" Skt. jánghā- "lower leg;" maybe somehow related to E. → shank.

qânuni (#)

Fr.: légal   

1) Permitted by law; lawful.
2) Of or relating to law; connected with the law or its administration (

From M.Fr. légal or directly from L. legalis "legal, pertaining to the law," from lex (genitive legis) "law."

Qânuni, of or relating to qânun, → law.


Fr.: légende   

1) A non-historical or unverifiable story handed down by tradition from earlier times and popularly accepted as historical.
2) The body of stories of this kind, especially as they relate to a particular people, group, or clan (

M.E. legende "written account of a saint's life," from O.Fr. legende and directly from M.L. legenda literally, "(things) to be read," noun use of feminine of L. legendus, gerund of legere "to read" (on certain days in church).

Cirok, from Kurd. cirok "story, fable," related to Kurd. cir-, cirin "to sing, [to recite?];" Av. kar- "to celebrate, praise;" Proto-Ir. *karH- "to praise, celebrate;" cf. Skt. kar- "to celebrate, praise;" O.Norse herma "report;" O.Prussian kirdit "to hear;" PIE *kerH2- "to celebrate" (Cheung 2007).


Fr.: légendaire   

Of, relating to, or of the nature of a legend.

legend; → -ary.

Legendre equation
  هموگش ِ لوژاندر   
hamugeš-e Legendre

Fr.: équation de Legendre   

The → differential equation of the form: d/dx(1 - x2)dy/dx) + n(n + 1)y = 0. The general solution of the Legendre equation is given by y = c1Pn(x) + c2Qn(x), where Pn(x) are Legendre polynomials and Qn(x) are called Legendre functions of the second kind.

Named after Adrien-Marie Legendre (1752-1833), a French mathematician who made important contributions to statistics, number theory, abstract algebra, and mathematical analysis; → equation.

Legendre transformation
  ترادیسش ِ لوژاندر   
tarâdiseš-e Legendre

Fr.: transformation de Legendre   

A mathematical operation that transforms one function into another. Two differentiable functions f and g are said to be Legendre transforms of each other if their first derivatives are inverse functions of each other: df(x)/dx = (dg(x)/dx)-1. The functions f and g are said to be related by a Legendre transformation.

Legendre equation; → transformation.

gânungozâri (#)

Fr.: législation   

1) The act of making or enacting laws.
2) A law or a body of laws enacted (

From Fr. législation, from L.L. legislationem, from legis latio, "proposing (literally 'bearing') of a law," → legislator.

Qânungoz&acric;ri "act or process followed by the qânungoz&acric;r", → legislator.

qânungozâr (#)

Fr.: législateur   

1) A person who gives or makes laws.
2) A member of a legislative body (

From L. legis lator "proposer of a law," from legis, genitive of lex, → law, + lator "proposer," agent noun of latus "borne, brought, carried."

Qânungozâr, literally "he who places the law," from qânun, → law, + gozâr, present stem and agent noun of gozâštan "to place, put; perform; allow, permit," related to gozaštan "to pass, to cross," → trans-

Lemaître Universe
  گیتی ِ لومتر   
giti-ye Lemaître (#)

Fr.: Univers de Lemaître   

A cosmological hypothesis, based on Einstein's relativity, in which the expanding Universe began from an exploding "primeval atom." In the Lemaître Universe the rate of expansion steadily decreases.

Named after Monsignor Georges Edouard Lemaître (1894-1966), a Belgian Roman Catholic priest, honorary prelate, professor of physics and astronomer; → universe.


Fr.: lemme   

1) A subsidiary proposition, proved for use in the proof of another proposition.
2) Linguistics: A word considered as its citation form together with all the → inflected forms. For example, the lemma go consists of go together with goes, going, went, and gone.
3) An argument or theme, especially when used as the subject or title of a composition (

From L. lemma, from Gk. lemma "something received or taken; an argument; something taken for granted," from root of lambanein "to take," → analemma.

Nehak, from neh present stem of nehâdan "to place, put; to set," → position, + -ak a diminutive suffix of nouns.

lemniscate of Bernoulli
  لمنیسکات ِ برنویی   
lemniskât-e Bernoulli

Fr.: lemniscate de Bernoulli   

A closed curve with two loops resembling a figure 8. It is represented by the Cartesian equation (x2 + y2)2 = a2(x2 - y2), where a is the greatest distance from the origin (pole) to the curve. Its polar equation is r2 = a2 cos 2θ.

From L. Latin lemniscatus "adorned with ribbons," from lemniscus "a pendent ribbon," from Gk. lemniskos "ribbon;" First described by Jacques Bernoulli (1654-1705) in 1694.

  درازا، طول   
derâzâ (#), tul (#)

Fr.: longueur   

A distance determined by the extent of something specified. → Jeans length

M.E. length(e), O.E. lengthu "length," from P.Gmc. *langitho, noun of quality from *langgaz (root of O.E. lang "long," cognate with Pers. derâz, as below) + -itho, abstract noun suffix. Cognate with O.N. lengd, O.Fris. lengethe, Du. lengte.

Derâzâ quality noun of derâz "long," variants Laki, Kurdi derež; Mid.Pers. drâz "long;" O.Pers. dargam "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time);" L. longus "long;" Gk. dolikhos "elongated;" O.H.G., Ger. lang; Goth. laggs "long;" PIE base *dlonghos- "long;" tul loan from Ar. ţaul, used in → wavelength.

length contraction
  ترنگش ِ درازا   
terengeš-e derâzâ

Fr.: contraction de longueur   

Same as → Lorentz contraction.

length; → contraction.

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