An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 694

Fr.: mélangeur   

In the → superheterodyne technique, the electronic component that lowers the frequency of the input signal and combines it with the signal coming from the → local oscillator to produce the → intermediate frequency signal. The lowered frequency, when amplified, has little chance to escape back into the antenna and produce feedback. Moreover, it is easier to make efficient amplifiers, filters, and other components for lower frequencies.

Agent noun from → mix.

âmizeš (#)

Fr.: mélange   

1) General: The process or result of irregular fluctuations in fluid motions on all scales from the molecular to large eddies.
2) Relating to → stellar interior, → mixing process.

Verbal noun of → mix.

mixing length
  درازای ِ آمیزش   
derâzâ-ye âmizeš

Fr.: longueur de mélange   

In a → turbulent flow, the average distance traveled by a → convective cell before it dissolves into its surroundings and deposits its energy. The mixing length is of the order of the → pressure scale height (HP), l = αHP, where α is the → mixing length parameter. See also → mixing length theory.

mixing; → length.

mixing length parameter
  پارامون ِ درازای ِ آمیزش   
pârâmun-e derâzâ-ye âmizeš

Fr.: paramètre de la longueur de mémange   

In the → mixing length theory, a parameter, α, that relates the → mixing length, l, to the → pressure scale height: α = l/HP. It is usually supposed that α is of order unity. Changes in α correspond to variations in the efficiency of the → convection, hence the transfer of heat.

mixing; → length; → parameter.

mixing length theory (MLT)
  نگره‌ی ِ درازای ِ آمیزش   
negare-ye derâzâ-ye âmizeš

Fr.: théorie de la longueur de mélange   

A theory dealing with heat transport by → turbulence which includes an elementary treatment of → convection. The central idea is that an unbalanced → buoyancy force drives a → convective cell to move through a distance, called the → mixing length, before the cell dissolves and joins the ambient medium. In this theory an adjustable → mixing length parameter  α is used. The theory, originally due to L. Prandtl (1925), was first applied to the Sun by L. Biermann (1932, Z. Astrophys. 5, 117).

mixing; → length; → theory.

mixing process
  فراروند ِ آمیزش   
farâravand-e âmizeš

Fr.: processus de mélange   

A process whereby → angular momentum and chemical species are transported from layer to layer within a star. The main mixing processes include: → convection, → overshooting, → rotation, and → turbulence. The extent to which the interiors of stars are mixed strongly influences their evolution, age, chemical content, and the relationship between their internal and surface → chemical abundances.

mixing; → process.

mixing ratio
  وابر ِ آمیزش   
vâbar-e âmizeš

Fr.:rapport de mélange   

Mass of water vapor per mass of dry air; expressed as grams per kilogram. → humidity

mixing; → ratio.

âmizé (#)

Fr.: mixture   

An aggregate of two or more substances that are not chemically combined with each other.

M.E., from L. mixtura "a mixing," from mixtus, → mix.

Âmizé, from âmiz present stem of âmixtan, → mix.

Mizar (ζ Ursae Majoris)
Me'zar (#)

Fr.: Mizar   

A star of visual magnitude 2.3 in the constellation → Ursa Major, which is the second star from the end of the → Big Dipper's handle. It forms a naked-eye double with → Alcor, lying at an angular separation of about 12 minutes of arc. Mizar is resolved into a 14''.4 → binary star (denoted A and B) with a probable period of thousands of years. Mizar A is a nearly equal-mass, → double-lined spectroscopic binary with period 20.54 days and → eccentricity of 0.53. The two components of Mizar A (denoted Aa and Ab) are both about 35 times as luminous as the Sun, and revolve around each other in about 20 days. Similarly, Mizar B is a → spectroscopic binary with a period of 175.57 days and an eccentricity of 0.46. Recent results suggest that Alcor is actually a binary and apparently → gravitationally bound to the Mizar system. This would make the Mizar-Alcor system a probable → sextuplet, lying at about 78 → light-years from Sun and the second closest such multiple known, after → Castor (Mamajek et al., 2010, AJ 139, 919).

Mizar, from Ar. al-Mi'zar (المءزر) "loin cloth, apron, veil."


Fr.: mJy   

A unit of → radio flux density, equal to 10-3 → jansky (Jy).

milli-; → jansky (Jy).

MK system


A system of stellar → spectral classification. The same as → Morgan-Keenan classification. Also called MKK system, → Yerkes system.

Morgan-Keenan classification.

MKS system
  راژمان ِ MKS   
râžmân-e MKS

Fr.: système MKS   

The system of → MKS units.

MKS unit; → system.

MKS units
  یکاهای ِ م.ک.ث.   
yekâhâ-ye MKS

Fr.: unités MKS   

The international system of units based on the → meter, → kilogram, and → second.

MKS, the initials of → meter, → kilogram, and → second; meter, kilogram, and second; → unit.

  یادسپار، یادسپاریک   
yâdsepâr (#), yâdsepârik

Fr.: mnémonique   

1) (adj.) Assisting or intended to assist the → memory.
2) (adj.) Pertaining to → mnemonics or to memory.
3) (n.) Something intended to assist the memory, as a verse or formula. For example, "Oh, Be A Fine Girl, Kiss Me Right Now Sweetheart!" is a mnemonic for the sequence of stellar → spectral types.

From Gk. mnemonikos "of or pertaining to memory," from mnemon "remembering, mindful," from mnasthai "remember," from PIE base *men- "to think;" cf. Pers. man-, -mân, minu, → idea.

Yâdsepâr, stem of Yâdsepârdan "memorize," from yâd "remembrance, recollection, memory" (Mid.Pers. ayâd) + sepârdan, sepor- "to yield, give, hand over" (Mid.Pers. abespâr- "to hand over, entrust;" cf. O.N. spara, O.H.G. sparon, O.E. sparian, E. spare); yâdsepârik, → mnemonics.


Fr.: mnémonique   

Something capable of assisting one's memory. The process or technique of improving the memory.

mnemonic; → -ics.


Fr.: mobile   

1) Capable of moving or being moved readily.
2) A mobile phone.

From M.Fr. mobile, from L. mobilis "movable, easy to move; loose, not firm," contraction of *movibilis, from movere "to → move."

Miyâvâ verval adj. and agent noun from miyâvidan, → move.

  مدی، مدمند   
modi, modmand

Fr.: modal   

Of or relating to mode, manner, or form.

mode; → -al.

  مدیگی، مدمندی   
modigi, modmandi

Fr.: modalité   

The quality or state of being → modal.

modal; → -ity.

  ترز، طرز، مُد   
tarz, mod

Fr.: mode   

1) Physics: Any of the distinct patterns of oscillation that a given periodically varying system can have.
2) Math.: In a series of statistical data, the item or value which occurs most frequently. It is a measure of central tendency.

Mode, from Fr. mode, from L. modus "measure, rhythm, song, manner," from PIE base *med- "to measure, limit, judge, advise;" cf. L. meditari "to think or reflect upon, consider;" Av. mad- "to measure out, apportion, allot;" Gk. medein "to rule;" O.E. metan "to measure out."

Tarz "manner, mode," Arabicized as طرز. Tarz may be related to Av. darəsa- "appearance, looking" (huuarə.darəsa- "having the appearance of the sun"), from Av. darəs- "to look;" cf. Skt. darś-, drś- "to see, appear, look, show" darśa- "apperance, look," drśta- "apparent, visible."
Mod, loan from Fr., cognate with Av. mad- "to measure out, apportion, allot," as above.

  ۱) مدل، ترزال؛ ۲) مدل‌ساختن، ترزالیدن   
1) (n.) model, tarzâl; 2) (v.) model sâxtan, tarzâlidan

Fr.: 1) modèle; 2) modéliser   

1a) A mathematical representation of a process, system, or object developed to understand its behavior or to make predictions. The representation always involves certain simplifications and assumptions. See also → theory, → hypothesis.
1b) A mental image of a phenomenon using familiar terms (or images). For example, in the Bohr model the atom is visualized as a nucleus with electrons orbiting around it in a manner similar to the way that planets revolve around the Sun. While this model is use ul in understanding the atom, it is an over-simplified description of a real atom and does not describe/predict all of its attributes (G. Smooth, Lawrence Berkeley Lab website).
2) To make or construct a model of.

M.Fr. modelle (Fr. modèle), from It. modello "a model, mold," from V.L. *modellus, from L. modulus "measure, standard," from modus "manner, measure" (cf. Av. mad-, → mode), PIE *med- + -ulus, → -ula.

1) Model, from Fr. modèle. Tarzâl, from tarz, → mode + -âl, → -al.
2) Model sâxtan, from model + sâxtan, sâzidan "to build, make, fashion; to adapt, adjust, be fit" (from Mid.Pers. sâxtan, sâz-, Manichean Parthian s'c'dn "to prepare, to form;" Av. sak- "to understand, to mark," sâcaya- (causative) "to teach").
Tarzâlidan, from tarzâl + -idan infinitive suffix.

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