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: 172
unbound cluster
  خوشه‌ی ِ نابندیده   
xuše-ye nâbandidé

Fr.: amas non lié   

A cluster of objects, such as stars or galaxies, in which the members are not tied together gravitationally. In such a cluster the members scatter through space following different directions. → bound cluster.

unbound; → cluster.

unbound system
  راژمان ِ نابندیده   
râžân-e nâbandidé

Fr.: système non lié   

An association of bodies which are not gravitationally tied together.

unbound; → system.

unbound young stellar system (UYSS)
  راژمان ِ ستاره‌ای ِ جوان ِ نابندیده   
râžmân-e setâre-yi-ye javân-e nâbandidé

Fr.: système stellaire jeune non lié   

A class of gravitationally loose stellar conglomerate with a notable apparent shape making it different from typical → bound  → star clusters. The UYSS class includes a large range of objects, which extend at various size scales and at various degrees of self-binding; from small (semi-)compact → unbound systems named → stellar associations, to huge extended superstructures of → massive stars that make up whole parts of Galactic → spiral arms, known as → stellar complexes (Gouliermis, D. A., 2018, PASP 130:072001; arXiv:1806.11541).

unbound; → young; → stellar; → system.

unbounded function
  کریای ِ بیکران   
karyâ-ye bikarân

Fr.: fonction non bornée   

The function y = f(x) in a given range of the argument x if there is no number M such that for all values of x in the range under consideration the inequality | f(x) | ≤ M will be fulfilled. → bounded function.

unbound; → function.

uncertainty
  ناتاشتیگی   
nâtâšigi (#)

Fr.: incertitude   

The state of being uncertain; unpredictability; indeterminacy. → uncertainty principle.

un- + → certainty.

uncertainty principle
  پَروَز ِ ناتاشتیگی   
parvaz-e nâtâštigi

Fr.: principe d'incertitude   

A quantum mechanical principle due to Werner Heisenberg which states that the position and momentum of a particle cannot be determined simultaneously with any arbitrary accuracy. These quantities can be determined only with accuracies limited by the relation Δx.Δp ≥ (1/2)ħ, where Δx is the error in the determination of the position and Δp is the error in the momentum. A similar relation holds for the energy of a particle and the time, ΔE.Δt ≥ (1/2)ħ. Same as → Heisenberg uncertainty principle.

uncertainty; → principle.

unclassified B[e] star (unclB[e])
  ستاره‌یِ B[e]ی ِ بی‌رده   
setâre-ye B[e]-ye bi radé

Fr.: étoile B[e] non-classée   

A temporary designation for a → B[e] star that cannot be placed in any of the four known classes.

classification; → B[e] star.

unclear
  نارونه   
nâruné

Fr.: non clair   

Difficult to see, hear, understand, or to be sure about.

un-; → clear.

unconditional
  نابوتاری، نابوتارمند   
nâbutâri, nâbutârmand

Fr.: inconditionnel   

Not limited by conditions; absolute.

un-; → conditional.

unconscious
  ناهاسن   
nâhâsan

Fr.: non conscient   

Not awake and aware; not responding to one's environment.

non-; → conscious.

unconsciousness
  ناهاسنی   
nâhâsani

Fr.: non conscience   

The → state of being → unconscious.

unconscious; → -ness.

unda
  شن-تل   
šen-tal

Fr.:   

A dune on a planetary surface, used in plural form undae.

From L. unda "wave," cognate with → water.

Šen-tal, from šen "sand" + tal "hill, heap."

under-
  کم-   

Fr.: sous-, faible   

A prefixal use of under, as to indicate place or situation below or beneath. Contrary to → over-.

M.E., from O.E. (cf. O.H.G. untar, Ger. unter, Goth. undar), from PIE *ndhero- "lower;" cf. Av. aδara- (adj.), aδairi- (prep.) "below;" Mid.Pers. êr "below, down; low, under," adar "low," azêr "below, under" (Mod.Pers. zir "below, down"); Skt. ádhara- "lower;" O.E. under "under, among").

Kam- "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few").

underabundance
  کم‌فراوانی   
kamfarâvâni

Fr.: sous-abondance   

The abundance of a chemical element being lower than a reference value, in particular compared to that of the Sun.

under-; → abundance.

underdamping
  کم‌میرایی   
kam-mirâyi

Fr.: amortissement faible   

The behavior of a damped system when the amount of damping is weak so that the system oscillates with the amplitude gradually decreasing to zero. → overdamping.

under-; → damping.

underestimate
  ۱) کم-بر‌آوردن؛ ۲) کم-بر‌آورد   
1) kam-baravardan; 2) kam-baravard

Fr.: 1) sous-estimer; 2) sous-estimation   

1) To estimate at too low a value, rate, or the like.
2) An estimate that is too low. → overestimate.

under-; → estimate

underqualified
  کمچونیمند   
kamcunimand

Fr.: sousqualifié   

Insufficiently qualified for a particular job (OxfordDictionaries.com).

under-; → qualified.

undersampling
  کم‌نمونان‌گیری   
kam-nemunângiri

Fr.: sous-échantillonage   

The circumstance in which there are not enough pixels in a star's image. The number of pixels that make up a star's image is determined by the relationship between the telescope focal length, the physical size of the pixels, and the size of the star's image. With an undersampled image it is not possible to obtain accurate estimates of the star's image size or its position. Undersampling occurs when the atmospheric seeing conditions are exceptionally good and the pixel size not small enough.

under-; → sampling.

understand
  فهمیدن   
fahmidan (#)

Fr.: comprendre   

To perceive the meaning of.

M.E. understanden, understonden, O.E. understandan "comprehend, grasp the idea of," probably literally "to stand in the midst of," from → under- + standan "to stand," cognate with Pers. istâdan, → standard.

Fahmidan, from Ar. fahm + infinitive suffix -idan.

understanding
  فهم   
fahm (#)

Fr.: compréhension, entendement, intelligence   

The ability to understand something; the → power of → abstract  → thought.

understand; → -ing.

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