An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 391

Fr.: nationalisation   

The transfer of a major branch of industry or commerce from private to state ownership or control (

nationalize; → -tion.


Fr.: nationaliser   

1) To bring under the ownership or control of a nation, as industries and land (

national; → -ize.


Fr.: naturel   

Occurring in nature; not artificially prepared. → nature.

Adj. of → nature.

natural frequency
  بسامد ِ زاستاری   
basâmad-e zâstâri

Fr.: fréquence naturelle   

Any frequency of small-amplitude oscillation for a system with a position of stable equilibrium and in the absence of external forces. In other words, the frequency of → free oscillation. Also called characteristic frequency.

natural; → frequency.

natural history
  تاریخ ِ زاستاری   
târix-e zâstâri

Fr.: histoire naturelle   

The → sciences, as → botany, → mineralogy, or → zoology, dealing with the study of all objects in → nature: used especially in reference to the beginnings of these sciences in former times (

natural; → history.

natural language
  زبان ِ زاستاری   
zabân-e zâstâri

Fr.: langage naturel   

Linguistics: A language that has evolved naturally as a means of communication among people, as opposed to → artificial language and → formal language (

natural; → language.

natural line broadening
  پهنش ِ زاستاری ِ خط   
pahneš-e zâstâri-ye xatt

Fr.: élargissement naturel de raie   

The broadening of any spectral line due to the fact that excited levels have mean lives, which, by virtue of the uncertainty principle, implies a spread in the energy values.

natural; → line; → broadening.

natural logarithm
  لگاریتم ِ زاستاری   
logâritm-e zâstâri

Fr.: logarithme naturel   

The logarithm in which the → base is the → irrational number e = 2.718281828.... Also called → Napierian logarithm. The natural logarithm is denoted ln, an abbreviation of logarithmus naturalis. Natural logarithms are related to → common logarithms through: ln x = (1/M) log x, with M = (1/ln 10) ≅ 0.434294.

natural; → logarithm.

natural number
  عدد ِ زاستاری   
adad-e zâstâri

Fr.: nombre naturel   

Either a member of the set of positive integers 1, 2, 3, ..., or the set of non-negative integers 0, 1, 2, 3, ... There seems to be no general agreement about whether to include 0 in the set of natural numbers.

natural; → number.

natural period
  دوره‌ی ِ زاستاری   
dowre-ye zâstâri

Fr.: période naturelle   

Of a body or system, the period of → free oscillation.

natural; → period.

natural resonance
  باز‌آوایی ِ زاستاری   
bâzâvâyi-ye zâstâri

Fr.: résonance naturelle   

A resonance such that the period of the driving force is the same as the natural period of the system.

natural; → resonance.

natural satellite
  ماهواره‌ی ِ زاستاری   
mâhvâre-ye zâstâri

Fr.: satellite naturel   

A solar system → object that → revolves around a → primary body and is not man made.

natural; → satellite.

natural science
  دانش ِ زاستاری   
dâneš-e zâstâri

Fr.: science naturelle   

A science that deals with matter, energy, their interrelations and transformations, In other words, natural sciences are concerned with physical processes observable in nature. They can be divided into physical and biological sciences.

natural; → science.

natural units
  یکاهای ِ زاستاری   
yekâhâ-ye zâstâri

Fr.: unités naturelles   

Physical units of measurement defined in terms of universal physical constants in such a manner that some chosen physical constants (e.g. the speed of light, Planck's constant, Boltzmann's constant, etc.) are equal to unity. The use of natural units allows these constants to be omitted from mathematical equations, leading to simpler calculations.

natural; → unit.

natural uranium
  اورانیوم ِ زاستاری   
urâniom-e zâstâri

Fr.: uranium naturel   

Uranium as found in nature. It contains 0.7% uranium-235, 99.3% uranium-238, and a trace of uranium-234 by weight.

natural; → uranium.

  زاستارگرایی، زاستارباوری   
zâstâr-gerâyi, zâstâr-bâvari

Fr.: naturalisme   

Philosophy: 1) The view of the world that takes account only of natural elements and forces, excluding the supernatural or spiritual.
2) The belief that all phenomena are covered by laws of science and that all teleological explanations are therefore without value (

natural; → -ism.


Fr.: nature   

The natural world as it exists without human beings or civilization.

M.E. natur(e), from O.Fr. nature from L. natura "the things at the outset, as it was when brought into existence; conditions of birth; essence, natural qualities," from natus "born," p.p. of nasci "to be born," from PIE *gen- "to give birth, beget," cognate with Pers. zâdan "to give birth," as below.

Zâstâr, literally "birth," from zâst past stem of [Dehxodâ] zâstan, variant of zâdan "to bring forth, give birth;" (Lâsgardi, Sorxeyi, Aftari) nestor "barren, sterile" (Mid.Pers. zâtan; Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born;" cf. Skt. janati "begets, bears;" L. gignere "to beget," nasci "to be born," as above, PIE base *gen- "to give birth, beget") + suffix -âr (forming verbal nouns as in raftâr, kerdâr, goftâr, didâr, jostâr, and so on; or forming accusative nouns, as in gereftâr, koštâr, etc.).

nautical astronomy
  اخترشناسی ِ دریانوردیک   
axtaršenâsi-ye daryâ-navardik

Fr.: astronomie nautique   

The branch of practical astronomy concerned with the determination of position and direction on sea by observation of celestial objects.

Nautical, from M.Fr. nautique, from L. nauticus "pertaining to ships or sailors," from Gk. nautikos, from nautes "sailor," from naus "ship," from PIE *nau- "boat;" cf. Pers. nâv "ship;" O.Pers./Av. *nāv-, O.Pers. nāviyā- "fleet;" Skt. nau-, nava- "ship, boat;" → astronomy.

Axtaršenâsiastronomy; daryâ-navardik, relating to daryâ-navardi "sea navigation," from daryâ "sea" (Mid.Pers. daryâp variant zrah; O.Pers. drayah-; Av. zrayah- "sea;" cf. Skt. jráyas- "expanse, space, flat surface") + navardi, noun of navardidan, navardan "to travel, walk, pass by and over" + -ik, → -ic.

nautical twilight
  نیمتاب ِ دریانوردیک   
nimtâb-e daryâ-navardik

Fr.: crépuscule nautique   

One of the three twilight phases which is the period before sunrise and after sunset when the center of the Sun's disk is between 6° and 12° below the horizon. This twilight phase is followed or preceded by → civil twilight. See also → astronomical twilight. In clear weather conditions, the horizon is faintly visible during this phase. Many of the brighter stars can also be seen, making it possible to use the position of the stars in relation to the horizon to navigate at sea. This is why it is called nautical twilight.

nautical astronomy; → twilight.

Navier-Stokes equation
  هموگش ِ ناویه-استوکس   
hamugeš-e Navier-Stokes

Fr.: équation de Navier-Stokes   

One of a set of → differential equations that describes the motion of a → fluid as a function of → pressure, → density, total external force, and → viscosity. See also → Euler equation.

Named after Claude-Louis Navier (1785-1836), a French engineer and physicist, and George Gabriel Stokes, → stokes; → equation.

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