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: 1022
porous dust grain
  دانه‌ی ِ غبار ِ پرلیک   
dâne-ye qobâr-e porlik

Fr.: grain de poussière poreux   

A type of → interstellar dust grain made up of an aggregate of components with a hollow structure. Various processes operating in interstellar and → circumstellar media are believed to produce inhomogeneous and porous dust grains. Porous grains can produce more → extinction per unit mass than their combined individual dust components. They are generally cooler than compact grains (see, e.g., Iati et al. 2001, MNRAS 322, 749).

porous; → dust; → grain.

Porrima (γ Vir)
  پوریما   
Porrimâ

Fr.: Porrima   

A → binary star in the constellation → Virgo comprising two yellow-white → main sequence stars of +3.6 and +3.7 magnitude and spectral types F0V. Their orbital period is about 170 years and they are about 40 light-years away.

Porrima after the Roman goddess of childbirth.

portal
  درگاه   
dargâh (#)

Fr.: portail   

A World Wide Web site that functions as an entry point to the Internet and is accessed through a browser.

M.E. portale "city gate, porch," from M. L. portalis (adj.) "of a gate," from L. porta "gate, door."

Dargâh, from Mid.Pers. dargâh "doorway," from dar "door" (O.Pers. duvara-; Av. dvar-; cf. Skt. dvár-; Gk. thura, L. fores; O.E. duru; E. door; Lith. dvaras "court-yard;" PIE *dhwer-/*dhwor- "door, gate") + gâh "place; time" (Mid.Pers. gâh, gâs; O.Pers. gāθu-; Av. gātav-, gātu- "place, throne, spot;" cf. Skt. gátu- "going, motion; free space for moving; place of abode;" PIE *gwem- "to go, come").

position
  ۱) نهش؛ ۲) نهش‌دادن   
1) neheš (#); 2) neheš-dâdan

Fr.: 1) position; 2) positionner   

1a) Condition with reference to place; location; situation.
1b) A place occupied or to be occupied. → mean position.
2a) To put in a particular or appropriate position; place.
2b) To determine the position of; locate.

M.E. posicioun, from O.Fr. posicion, from L. positionem "act or fact of placing, position, affirmation," from positus, p.p. stem of ponere "to put, place."

Neheš, verbal noun from nehâdan "to place, put; to set;" Mid.Pers. nihâtan, from ne-, ni- "down; into," → ni- (PIE), + dâ- "to put; to establish; to give," dadâiti "he gives;" cf. Skt. dadâti "he gives;" Gk. didomi "I give;" L. do "I give;" PIE base *do- "to give"). Neheš-dâdan, from neheš "position," + dâdan "to give, yield, put," → datum.

position angle
  زاویه‌ی ِ نهش   
zâviye-ye neheš

Fr.: angle de position   

The convention for measuring angles on the sky in astronomy (Abbreviated as PA). It is the direction of an imaginary arrow in the sky, measured from north through east: 0° = north, 90° = east, 180° = south, and so on to 359° and back to 0°. Applied to a binary system it is the direction of a secondary body or feature from a primary, measured in the system. .

position; → angle.

position switching
  دگربانی ِ نهش   
degarbâni-ye neheš

Fr.: permutation de position   

In single dish astronomy, an observing mode in which the telescope is moved between the object position and a user defined reference position. The aim is to eliminate unwanted signals in the baseline. → beam switching; → frequency switching.

position; → switching.

positional
  نهشی   
neheši (#)

Fr.: de position, positionnel   

Relating to or determined by position.

position; → -al.

positional astronomy
  اخترشناسی ِ نهشی   
axtaršenâsi-ye neheši

Fr.: astronomie de position   

The branch of astronomy that is used to determine the location of objects on the celestial sphere, as seen at a particular date, time, and location on the Earth. Same as → spherical astronomy.

positional; → astronomy.

positional notation
  نمادگان ِ نهشی   
nemâdgân-e neheši

Fr.: notation positionnelle   

A system of representing → numbers in which the → position of a → digit in a string of digits affects its value. The decimal system is a positional notation for expressing numbers. Same as → place-value notation and → positional number system.

positional; → notation.

positional number system
  راژمان ِ عددی ِ نهشی   
râžmân-e adadi-ye neheši

Fr.: système de numération positionnel   

A → number system in which the value of each digit is determined by which place it appears in the full number. The lowest place value is the rightmost position, and each successive position to the left has a higher place value. In the → number system conversion, the rightmost position represents the "ones" column, the next position represents the "tens" column, the next position represents "hundreds", etc. The values of each position correspond to powers of the → base of the number system. For example, in the usual decimal number system, which uses base 10, the place values correspond to powers of 10. Same as → place-value notation and → positional notation. See also → number system conversion.

positional; → number; → system.

positioning
  نهش‌داد، نهشداد   
nehešdâd

Fr.: positionnement   

The act or process of putting in a particular position or determining the psition of.

Verbal noun of → position; → -ing.

positive
  داهیدار   
dâhidâr

Fr.: positif   

1) General: Explicitly stated, stipulated, or expressed.
2) Capable of being measured, detected, or perceived.
3) Math.: Noting a quantity greater than zero.
4) Physics: Having an electrical charge of the same polarity as that of a proton.
5) Photography: Having colors or values of dark and light corresponding to the subject.
6) Philosophy: Relating to the theory that knowledge can be acquired only through direct observation and experimentation, and not through metaphysics or theology. → positivism.
7) Law: Conclusive and beyond doubt or question; irrefutable.
8) Opposite of → negative.
See also:
positive charge, → positive correlation, → positive feedback, → positive skewness, → positiveness, → positivism.

M.E., from O.Fr. positif, from L. positivus "placed, settled; positive" (opposed to naturalis "natural"), from posit-, from positus "placed, put," p.p. of ponere "to put, place, set" + -ivus a suffix of adjectives.

Dâhidâr, from dâhid- + -âr. The first component is the past stem of *dâhidan "to put, create, determine," variant of dehidan, dâdan "to give;" from Mid.Pers. dâdan, dahidan "to give; to create;" O.Pers. dā- "to give, grant, yield;" Av. dā- "to give, grant; put; create; determine;" dāhi "he would give/put" (single second person, subjunctive transitive), dadāiti "he gives;" cf. Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer," facere "to do, to make;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do." The second component -âr, accusative suffix; on the model of gereftâr "captive, involved (in trouble)," didâr "exposed to view."

positive charge
  بار ِ داهیدار   
bâr-e dâhidâr

Fr.: charge positive   

A charge having sign opposite to that of the electron.

positive; → charge.

positive correlation
  هم‌باز‌آنش ِ داهیدار   
hambâzâneš-e dâhidâr

Fr.: correlation positive   

Same as → direct correlation.

positive; → correlation.

positive feedback
  بازخورد ِ داهیدار   
bâzxord-e dâhidâr

Fr.: rétroaction positive   

A → feedback process in which the → output reacts on the → input so as to increase the initial → effect.

positive; → feedback.

positive skewness
  کژالی ِ داهیدار   
kažâli-ye dâhidâr

Fr.: asymétrie positive   

Of a distribution function, a skewness in which the right tail (tail at the large end of the distribution) is more pronounced than the left tail (tail at small end of the distribution). → negative skewness.

positive; → skewness.

positiveness
  داهیداری   
dâhidâri

Fr.: positivité   

The quality or state of being positive; positivity.

positive + → -ity.

positivism
  داهیدارباوری   
dâhidârbâvari

Fr.: positivisme   

Any doctrine that excludes a priori affirmations and admits only positive truth, i.e. factual knowledge gained through observation.

From Fr. positivisme, from positif, → positive, in its philosophical sense of "imposed on the mind by experience;" → -ism.

positron
  پوزیترون   
pozitron

Fr.: positron   

The antiparticle of the electron, which has the same mass, spin, and charge as the electron, but the charge is positive. Positrons may be generated by radioactive decay or by pair production from energetic gamma photons.

From posi(tive), → positive + (elec)tronelectron.

positronium
  پوزیترونیوم   
pozitroniom

Fr.: positronium   

A short-lived bound state of a positron and an electron.

From → positron + -ium (as in barium, titanium), from N.L., from L. neuter suffix.

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