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: 692
diffusivity
  پخشندگی، همگر ِ پخش   
paxšandegi, hamgar-e paxš

Fr.: coefficient de diffusion   

1) The ability to permit or undergo diffusion.
2) → magnetic diffusivity.

diffusive; → -ity.

digit
  رقم   
raqam (#)

Fr.: chiffre   

A symbol, numeral, or graphic character that represents an integer.

From L. digitus "finger, toe."

Raqam, from Ar.

digital
  رقمی   
raqami (#)

Fr.: numérique   

1) Of or pertaining to a digit.
2) Representing data as a series of numerical values. Often opposed to → analogue.

digit + → -al.

digital computer
  رایانگر ِ رقمی   
râyângar-e raqami (#)

Fr.: ordinateur numérique   

A computer that accepts and operates with → discrete data in the form of combinations of digits, letters, or other characters. In modern terminology, generally called computer.

digital + → computer.

digitize
  رقمیدن   
raqamidan (#)

Fr.: numériser   

To convert an → analogue signal to a → digital signal that represents the same information as the analogue signal.

digit + → -ize.

dihedral
  دودیمه‌ای   
dodime-yi

Fr.: dihédral   

1) Having formed by two half-planes which intersect.
2) Of or relating to a → dihedron.

dihedron; → -al.

dihedral angle
  زاویه‌ی ِ دودیمی   
zâviye-ye dodimi

Fr.: angle dièdre   

An angle formed by two planes meeting along a common line. Compare with → face angle.

angle; → dihedral.

dihedron
  دودیمه   
dodimé

Fr.: dièdre   

A figure formed by two intersecting planes.

di-; → -hedron.

dilate
  ۱) فراخاندن؛ ۲) فراخیدن   
1) farâxândan; 2) farâxidan (#)

Fr.: 1) dilater; 2) se dilater   

1) (v.tr.) To make wider or larger; cause to expand.
2) (v.intr.) To spread out; expand.

M.E. dilaten, from O.Fr. dilater, from L. dilatare "make wider, enlarge," from → dis- "apart" + latus "wide," → latitude.

Farâxândan, farâxidan, infinitive from farâx "broad, wide, spacious;" Mid.Pers. frâxv, fraxv "broad, wide," frâxvitan, frâxvênitan "to spread."

dilation
  فراخش   
farâxeš (#)

Fr.: dilatation   

The act of dilating; state of being dilated. Also dilatation.
Physics: The increase in volume per unit volume of a homogeneous substance. → time dilation.

Verbal noun of → dilate.

dilute
  ۱) اوتال؛ ۲) اوتالیدن   
1) owtâl; 2) owtâlidan

Fr.: 1) dilué; 2) diluer   

1) (adj.) Describing a solution that is reduced in concentration.
2) (v.tr.) To make a solution thinner by the addition of water or the like.

From L. dilutus, p.p. of diluere "dissolve, wash away," from → dis- "apart" + -luere, combining form of lavere "to wash;" cf. Pers. lur "flood" [Mo'in, Dehxodâ] (variants Lori, Kordi: laf, lafow, lafaw, Tabari: ); Gk. louein "to wash;" Bret. laouer "trough;" PIE base *lou- "to wash."

Owtâl, from Tabari utâl, "having water, impregnated with water, waterlogged," from ow "water," → water + tâl variant of dâr "having, possessor," from dâštan "to have, to possess" (Mid.Pers. dâštan; O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind;" Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE base *dher- "to hold, support").

dilution
  اوتالش   
owtâleš

Fr.: dilution   

The process of reducing the concentration of solute in a solution by increasing the proportion of solvent.

Verbal noun of → dilute.

dilution factor
  کروند ِ اوتالش   
karvand-e owtâleš

Fr.: facteur de dilution   

The energy density of a radiation field divided by the equilibrium value for the same color temperature.

dilution; → factor.

dim
  تیره   
tiré (#)

Fr.: faible, pâle, mat(e)   

Not bright; obscure from lack of light.

O.E. dimm "dark, gloomy, obscure," from P.Gmc. *dimbaz.

Tiré, from Mid.Pers. têrag, variant of târig "dark," Av. taθra- "darkness," taθrya- "dark," cf. Skt. támisrâ- "darkness, dark night," L. tenebrae "darkness," Hittite taš(u)uant- "blind," O.H.G. demar "twilight."

dimension
  وامون   
vâmun

Fr.: dimension   

1) Math.: Independent extension in a given direction; a property of space.
2) Physics: → physical dimension.

From L. dimensionem (nom. dimensio), from stem of dimetri "to measure out," from → dis- + metri "to measure."

Vâmun, from vâ-, → dis-, + mun, variant mân "measure" (as in Pers. terms pirâmun "perimeter," âzmun "test, trial," peymân "measuring, agreement," peymâné "a measure; a cup, bowl"), from O.Pers./Av. mā(y)- "to measure;" PIE base *me- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum.

dimensional
  وامونی   
vâmuni

Fr.: dimensionnel   

Of or pertaining to → dimension.

dimension; → -al.

dimensional analysis
  آنالس ِ وامونی، آناکاوی ِ ~   
ânâlas-e vâmuni, ânâkâvi-ye ~

Fr.: analyse dimensionnelle   

A technique used in physics based on the fact that the various terms in a physical equation must have identical → dimensional formulae if the equation is to be true for all consistent systems of unit. Its main uses are:
a) To test the probable correctness of an equation between physical quantities.
b) To provide a safe method of changing the units in a physical quantity.
c) To solve partially a physical probable whose direct solution cannot be achieved by normal methods.

dimensional; → analysis.

dimensional formula
  دیسول ِ وامونی   
disul-e vâmuni

Fr.: formule dimensionnelle   

Symbolic representation of the definition of a physical quantity obtained from its units of measurement. For example, with M = mass, L = length, T = time, area = L2, velocity = LT-1, energy = ML2T-2. → dimensional analysis.

dimensional; → formula.

dimensionless quantity
  چندی ِ بی‌وامون   
candi-ye bivâmun

Fr.: quantité sans dimension   

A quantity without an associated → physical dimension. Dimensionless quantities are defined as the ratio of two quantities with the same dimension. The magnitude of such quantities is independent of the system of units used. A dimensionless quantity is not always a ratio; for instance, the number of people in a room is a dimensionless quantity. Examples include the → Alfven Mach number, → Ekman number, → Froude number, → Mach number, → Prandtl number, → Rayleigh number, → Reynolds number, → Richardson number, → Rossby number, → Toomre parameter. See also → large number.

dimension + -less M.E. from O.E. læs (adv.), læssa (adj.), akin to O.Fr. les "less."

Bi- "without," → a-, + vâmun, → dimension.

dimer
  دی‌مر   
dimer

Fr.: dimère   

A molecule resulting from combination of two identical molecules.

From → di- "two, twice, double," + -mer a combining form denoting member of a particular group, → isomer.

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