# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

Homepage

Number of Results: 1039
 power function   کریای ِ توانی   karyâ-ye tavâniFr.: fonction de puissance   A function of the form f(x) = xn, where n is a → real number.→ power; → function. power law   قانون ِ توانی   qânun-e tavâni (#)Fr.: loi de puissance   A mathematical relationship between two quantities expressed by a → power function.→ power; → law. power series   سری ِ توانی   seri-ye tavâni (#)Fr.: série de puissance   A series in which the terms contain regularly increasing powers of a variable. In general, a0 + a1x + a2x2 + ... + anxn, where a0, a1, etc. are constants.→ power; → series. power spectral density   چگالی ِ بینابی ِ توان   cagâli-ye binâbi-ye tavânFr.: densité spectrale de puissance   Same as → spectral density.→ power; → spectral; → density. power spectrum   بیناب ِ توانی   binâb-e tavâni (#)Fr.: spectre de puissance   The plot that gives the portion of a signal's power falling within given frequency bins. The most common way of generating a power spectrum is by using a discrete Fourier transform.→ power; → spectrum. power-law distribution   واباژش با قانون ِ توانی   vâbâžeš bâ qânun-e tavâniFr.: distribution en loi de puissance   For a → random variable X, any → distribution which has the form: P(X ≥ x) = (k/x)α, where x is a value in the range defined for X, k > 0 is a parameter termed location parameter, and α > 0 is the → slope parameter.→ power; → law; → distribution. power-law elliptical galaxy   کهکشان ِ بیضی‌گون با قانون ِ توانی   kahkešân-e beyzigun bâ qânun-e tavâniFr.: galaxie elliptique en loi de puissance   An → elliptical galaxy whose → surface brightness can be approximated by a single → power law at small radii (r ≤ 10-20''). More modern interpretations have emphasized that these profiles can be better understood as the inward continuation of the galaxy's overall → Sersic profile, usually modified by an additional, nuclear-scale stellar component (S. P. Rusli et al., 2013, AJ 146, 160).→ power; → law; → galaxy. Poynting vector   بردار ِ پوینتینگ   bordâr-e PoyntingFr.: vecteur de Poynting   The amount of electromagnetic energy flowing through unit area, perpendicular to the direction of energy propagation, per unit time, given by (c/2 π)[E x H]. → Poynting's theorem. Poynting's theorem   فربین ِ پوینتینگ   farbin-e PoyntingFr.: théorème de Poynting   The space through which electromagnetic radiation passes is filled with electric and magnetic fields at right angles to each other and to the direction of propagation of the radiation. The rate of energy transfer is given by the Poynting vector.In honor of John Henry Poynting (1852-1914), English physicist; → theorem. Poynting-Robertson drag   کره‌ی ِ پوینتینگ-رابرتسون   kerre-ye Poynting-RobertsonFr.: traînée de Poynting-Robertson   A loss of → orbital angular momentum by tiny ring particles associated with their absorption and re-emission of → solar radiation. Also known as the → Poynting-Robertson effect (Ellis et al., 2007, Planetary Ring Systems, Springer). Poynting-Robertson effect   ا ُسکر ِ پوینتینگ-رابرتسون   oskar-e Poynting-RobertsonFr.: effet Poynting-Robertson   The effect of → solar radiation on a small (centimeter-sized) particle in → orbit around the Sun that causes it to lose velocity and fall gradually into the Sun. The particle → absorbs solar radiation and → radiates the energy → isotropically in its own frame. The particle thereby preferentially radiates (and loses → angular momentum) in the forward direction in the → inertial frame of the Sun (aberration effect). This leads to a decrease in the particle's angular momentum and causes it to spiral sunward. In contrast, the → Yarkovsky effect is anisotropic; the object may be accelerated or decelerated.→ Poynting's theorem; Howard Percy Robertson (1903-1961), American physicist and mathematician; → effect. practicable   ورز‌پذیر، ورزیدنی   varzpazir, varzidaniFr.: praticable   That can be done or used or put into practice.→ practice; → -able. practical   ورزال   varzâlFr.: pratique   Concerned with practice, as opposed to → theory.→ practice; → -al. practice   ۱) ورزیدن؛ ۲) ورزه   1) varzidan (#); 2) varzé (#)Fr.: 1) pratiquer; 2) pratique   1a) To do habitually or regularly. 1b) To exercise or follow as a profession. 2a) Performance; the doing of something (contrasted with → theory). See also → praxis. 2b) Way of doing something that is common or habitual. 2c) Frequent or systematic repetition in doing something.M.E. practisen, practizen; O.Fr. practiser "to practice," from M.L. practicare "to do, perform," from L.L. practicus "practical," from Gk. praktikos "practical."1) Varzidan "to practice, perform; to accustom oneself to; to labor; to sow a field;" Mid.Pers. warz- "to work, do, practice;" Av. varəz- "to work, do, perform, exercise;" cf. Gk. ergon "work;" Arm. gorc "work;" Lith. verziu "tie, fasten, squeeze," vargas "need, distress;" Goth. waurkjan; O.E. wyrcan "work," wrecan "to drive, hunt, pursue;" E. work; PIE base *werg- "to work." 2) varzé, noun from present stem varz- + suffix -é. practicing   ورزنده   varzandéFr.: pratiquant   Actively following a specified career or way of life.→ practice; → -ing. practitioner   ورزمند   varzmandFr.: praticien   A professional man, especially in medicine and the law.Alteration of practician, → practice (+ -ian) + -er, → -or.Varzmand, from varz, → practice, + -mand, → -ist. Praesepe   پرایسپه، کندو، آخور   Perâysepé, Kandu, ÂxorFr.: la Crèche   An → open cluster in the constellation → Cancer containing about 50 stars of 6th magnitude or fainter. It lies 577 light-years away. Also called NGC 2632, the Beehive Cluster, or the Manger.From L. praesepe "crib," from which cattle or horses are fed, manger; the neighboring brighter stars Gamma and Delta Cancri (Asellus Borealis and Asellus Australis) were pictured as asses which fed from a manger.Perâysepé, loan from L., as above. Kandu "beehive; a large earthen vessel in which grain is kept;" cf. Skt. kunda- "a bowl-shaped vessel, basin; the lower abdomen." &ACIRC;xor "manger," prefixed xor "to eat" (semantically like E. manger, Fr. mangeoire, from L. manducare, mandere "to chew, eat"), from Mid.Pers. âxwarr; Av. avô-xvarəna- "drinking fountain; a water spring," from avô- "water" + xvarəna-, from xvar- "to consume, eat;" Mid.Pers. xvardan "to eat, enjoy (food);" Mod.Pers. xordan "to eat, drink, devour," Laki dialect hovârden "to eat;" Proto-Iranian *huar- "to consume, eat." pragmatic   ورزال‌گرا   varzâl-gerâFr.: pragmatique   Concerned with practical results and values; treating things in a practical way.M.Fr. pragmatique, from L. pragmaticus "skilled in business or law," from Gk. pragmatikos "versed in business," from pragma (genitive pragmatos) "civil business, deed, act," from prassein "to do, act, perform."Varzâl-gerâ, literally "practice-inclined," from varzâl, → practical, + -gerâ "inclining toward, intending, making for," → -ist. pragmatics   ورزال‌گراییک   varzâl-gerâyikFr.: pragmatique   A branch of → semiotics dealing with the relation between language and the users, especially the constraints they encounter in using language in social interaction, and the corresponding effects on other users in the communication.→ pragmatic; → -ics. pragmatism   ورزال‌گرایی   varzâl-gerâyiFr.: pragmatisme   Philo.: The doctrine that the truth or value of a concept or assertion is determined by its practical effects upon human interests.→ pragmatic; → -ism.