An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 360
numeral system
  راژمان ِ عددی، ~ عددها   
râžmân-e adadi, é adadhâ

Fr.: système de numération   

A set of → symbols and → rules for representing → numbers. Same as → number system. See also: → Greek numeral system, → Roman numeral system, → Indian numeral system.

numeral; → system.

numerator
  شماران   
šomârân (#)

Fr.: numérateur   

The quantity x in a fraction x/y). The quantity y is the → denominator.

L.L. numerator "a counter, numberer," from L. numera(re) "to number," → number + -tor a suffix forming personal agent nouns from verbs and, less commonly, from nouns.

Šomârân, agent noun of šomârdan, → number.

numerical
  عددی   
adadi (#)

Fr.: numérique   

Relating to or expressed in numbers.

Adj. of → number.

numerical analysis
  آنالس ِ عددی   
ânâlas-e adadi

Fr.: analyse numérique   

The study of methods for approximation of solutions of various classes of mathematical problems including error analysis.

numerical; → analysis.

numerical modeling
  مدل‌سازی ِ عددی، ترزال‌سازی ِ ~   
modelsâzi-ye adadi (#), tarzâlsâzi-ye ~

Fr.: modélisation numérique   

The prediction of the evolution of a system via numerical construction of approximate solutions to the governing equations.

numerical; → modeling.

numerical simulation
  مانندش ِ عددی، همانندسازی ِ ~   
mânandeš-e adadi, hamânand sâzi-ye ~

Fr.: simulation numérique   

Another name for → numerical modeling.

numerical; → simulation.

Nunki (σ Sagittarii)
  نونکی   
Nunki

Fr.: Nunki   

The second brightest star in the constellation → Sagittarius. It is a blue-white → massive star of → spectral type B2.5 V lying 225 → light-years away.

Unusual name of Babylonian origin, of unknown significance.

nutate
  کلتاویدن   
kaltâvidan

Fr.: osciller   

To undergo or show nutation.

Nutate, back formation from → nutation.

Kaltâvidan, verbal form of → kaltâvnutation.

nutation
  کلتاو   
kaltâv

Fr.: nutation   

Mechanics: A wobbling motion of a spinning rigid body, such as a top, as it precesses about its vertical axis.
Astro.: A slight nodding motion of the Earth's axis of rotation, which has a principal period of 18.6 years. It is primarily caused by lunar perturbations, and is superimposed on the precession of the equinoxes and moves the equinox as much as 17'' ahead of or behind its mean position.

Fromm L. nutation-, from nutat(us), p.p. of nutare "to wobble, to sway, to nod repeatedly," from nu "nod" + -ta frequentative suffix + -tus p.p. ending + -ion a suffix denoting action or condition.

Kaltâv, from Kermâni keletow, Malâyeri kallatow "wobbling," from kal, kalleh "head" + tâv, tow, tâb "swing, twist," from tâbidan "to twist, to spin."

nutation in right ascension
  کلتاو ِ راست‌افراز   
kaltâv-e râst-afrâz

Fr.: nutation en ascension droite   

Same as → equation of the equinoxes.

nutation; → right ascension.

nutator
  کلتاوگر، کلتاونده   
kaltâvgar, kaltâvandé

Fr.:   

A drive mechanism used to move a radar beam in a circular, spiral, or conical path periodically.

Agent noun of → nutate.

nutrient
  فارمند   
fârmand

Fr.: nutritif   

1) Nourishing; providing nourishment or nutriment.
2) Containing or conveying nutriment, as solutions or vessels of the body.
3) A nutrient substance (Dictionary.com).

From L. nutrientem, pr.p. of nutrire, → nourish.

Fârmand, from present stem of fâridan, + -mand.

nutriment
  فاراک   
fârâk

Fr.: nourriture   

1) Any substance or matter that, taken into a living organism, serves to sustain it in its existence, promoting growth, replacing loss, and providing energy.
2) Anything that nourishes; nourishment; food (Dictionary.com).

From L. nutrimentum "nourishment; support," from nutrire, → nourish.

Fârâk, from present stem of fâridan, → nourish, + -âk (as in xorâk, pušâk, etc.).

nutrition
  فارش   
fâreš

Fr.: nutrition, alimentation   

1) The act or process of nourishing or of being nourished.
2) The science or study of, or a course of study in, nutrition, especially of humans (Dictionary.com).

Verbal noun from L. nutrire, → nourish.

nutritionist
  فارشگر   
fârešgar

Fr.: nutritioniste   

A person who is trained or expert in the science of nutrition.

nutrition; → -ist.

nutritive
  فارنده   
fârandé

Fr.: nutritif, nourrissant   

1) Serving to nourish; providing nutriment; nutritious.
2) Of, pertaining to, or concerned with nutrition (Dictionary.com).

Adjective and agent noun from L. nutrire, → nourish.

nyctalopia
  شبکوری   
šabkuri (#)

Fr.: nyctalopie   

Same as → night blindness; opposite of → hemeralopia.

L.L. nyctalopia, from Gk. nukt, → night + al(aos) "blind" + -opia, akin to ope "view, look," ops "eye."

Šabkuri, from šab, → night, + kuri "blindness," from kur, → blind.

Nyquist formula
  دیسول ِ نیکویءیست   
disul-e Nyquist

Fr.: formule de Nyquist   

The mean square noise voltage across a resistance in thermal equilibrium is four times the product of the resistance, Boltzmann's constant, the absolute temperature, and the frequency range within which the voltage is measured. → Johnson-Nyquist noise.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory. → Johnson-Nyquist noise; → formula.

Nyquist frequency
  بسامد ِ نیکویءیست   
basâmad-e Nyquist

Fr.: fréquence de Nyquist   

The highest frequency that can be determined in a Fourier analysis of a discrete sampling of data.

Nyquist formula; → frequency.

Nyquist-Shannon sampling theorem
  فربین ِ نمونان‌گیری ِ نیکویءیست-شانون   
farbin-e nemunân-giri-ye Nyquist-Shannon

Fr.: théorème d'échantillonnage de Nyquist-Shannon   

The minimum number of resolution elements required to properly sample a signal, such as a star image, without causing erroneous effects known as aliasing. For electronic imaging, this number is generally taken as 2 pixels across the seeing disk diameter at the half intensity points. Also called → Shannon's sampling theorem and → sampling theorem.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory, and Claude Elwood Shannon (1916-2001), an American mathematician and pioneer of information theory; → theorem.

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