An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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 linear approximation   نزدینش ِ خطی   nazdineš-e xattiFr.: approximation linéaire   Taking the first term in the Taylor series as an approximation to a mathematical function at a given point. → first approximation.→ linear; → approximation. linear correlation   هم‌باز‌آنش ِ خطی   hambâzâneš-e xattiFr.: corrélation linéaire   A measure of how well data points fit a straight line. When all the points fall on the line it is called a perfect correlation. When the points are scattered all over the graph there is no correlation.→ linear; → correlation. linear differential equation   هموگش ِ دگرسانه‌ای ِ خطی   hamugeš-e degarsâne-yi-ye xattiFr.: équation différentielle linéaire   An equation in which the → dependent variable y and all its differential coefficients occur only in the first degree. A linear differential equation of → order  order n has the form: fn(x)y(n) + fn-1(x)y(n-1) + ... + f1(x)y' + f0(x)y = Q(x), where f0(x), f1(x), ..., fn(x) and Q(x) are each continuous functions of x defined on a common interval I and fn(x)≠ 0 in I. A linear differential equation cannot have, for example, terms such as y2 or (y')1/2. See also: → homogeneous linear differential equation; → nonhomogeneous linear differential equation.→ linear; → differential; → equation. linear equation   هموگش ِ خطی   hamugeš-e xattiFr.: équation linéaire   An equation composed of first degree variables and representing a straight line.→ linear; → equation. linear function   کریای ِ خطی   karyâ-ye xattiFr.: fonction linéaire   A function expressed by a → first degree equation that can be graphically represented in the → Cartesian coordinate plane by a → straight line.→ linear; → function. linear perturbation theory   نگره‌ی ِ پرتورش ِ خطی   negare-ye partureš-e xattiFr.: théorie de perturbation linéaire   Assumption that the variations in the plasma parameters, due to the presence of waves, are small (to the first order) as compared to the undisturbed parameters. This makes it possible to linearize equations by dropping out second order (and higher) nonlinear terms.→ linear; → perturbation; → theory. linear polarization   قطبش ِ خطی   qotbeš-e xatti (#)Fr.: polarisation linéaire   Of an electromagnetic radiation, a → polarization in which the electric vibrations are confined to one plane along the direction of propagation. Also called → plane polarization. See also → circular polarization.→ linear; → polarization. linear regression   وایازی ِ خطی   vâyâzi-ye xattiFr.: regression linéaire   In statistics, a regression method that establishes a linear relationship between two random variables.→ linear; → regression. linearization   خطش، خطانش   xatteš, xattânešFr.: linéarisation   A process of reduction to linear form by appropriate change of variables or by approximation.Verbal noun of → linearize. linearized differential equation   هموگش ِ دگرسانه‌ای ِ خطی   hamugeš-e degarsâneyi-ye xattiFr.: équation différentielle linéarisée   A differential equation that has been derived from an original nonlinear equation.Linearized, p.p. of → linearize; → differential; → equation. lion   شیر   šir (#)Fr.: lion   A large, usually tawny-yellow cat, Panthera leo, native to Africa and southern Asia, having a tufted tail and, in the male, a large mane (dictionary.com).M.E., from O.Fr., variant of leon, from L. leon- (stem of leo), from Gk. leon.Mid.Pers. šagr "lion;" cf. Parth. šarg; Sogd. šarγu "lion;" its O.Pers. and Av. forms are not extant. Šir may be cognate with Skt. kēsarin- "lion; literally maned," from kēsar- "mane;" PIE *kaisar- "mane; hairs." If so, šir could be related to PIE *kaisaraka-, provided that the the initial *kai- is dropped and *saraka- has transformed in *sarg, šarg, šir. liquefaction   آوش   âvešFr.: liquéfaction   1) The act or process of liquefying or making liquid. 2) The state of being liquefied.→ liquefy; → -tion. local position invariance   ناورتایی ِ نهش ِ محلی   nâvartâyi-ye neheš-e mahaliFr.: invariance de position locale   → local; → position; → invariance. localization   محل‌گیری   mahal giri (#)Fr.: localisation   The condition of the wave-function of an electron if it is confined to a small region of a large system rather than being extended through the system.Verbal noun of → localize. logarithmic extinction   خاموشی ِ لگاریتمی   xâmuši-ye logâritmiFr.: extinction logarithmique   Same as → reddening coefficient. logical connective   هابندار ِ گوییکی   hâbandâr-e guyikiFr.: connecteur logique   A symbol that can be combined with one or more → sentences in order to form a new sentence. For example "and" (∧), "or" (∨) "not" (¬), "if-then" (→), and "iff" (⇔).→ logical; → connective. lognormal distribution   واباژش ِ لگاریتمی-هنجارور   vâbâžeš-e logâritmi-hanjârvarFr.: distribution logarithmico-normale   A → probability distribution in which the natural logarithm (logX) of the → random variable (X) has a → Gaussian distribution. long   دراز   derâz (#)Fr.: long   1) Having considerable linear extent in space. → very-long-baseline interferometry (VLBI). 2) Having considerable duration in time. → long-period variable.M.E. longe, O.E. lang, long, akin to O.H.G., Ger. lang "long," O.N. langr, M.Du. lanc, Goth. laggs "long," L. longus, → longitude.Derâz "long," Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time)." long-period comet   دمدار ِ درازدوره   domdâr-e derâz dowréFr.: comète à longue période   A comet with orbital period of more than 200 years. → short-period comet; → periodic comet.→ long; → period; → comet. long-period variable   ورتنده‌ی ِ درازدوره   vartande-ye derâz dowréFr.: variable à longue période   A type of → variable star in which variations in brightness occur over long time-scales of months or years. The term generally refers to → Mira variable types.→ long; → period; → variable.