An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -ph pal par par par par Pas pat Pel per per per per Per per pha phi pho pho pho phy pip Pla pla pla pla ple poa pol pol pol pol pop pos pos pow pra pre pre pre pri pri pri pro pro pro pro pro pro pse pul pup > >>

Number of Results: 1037

Fr.: population   

Statistics: Any finite or infinite set of individuals, items, or data subject to a statistical study. → disk population; → halo population; → population inversion; → Bose-Einstein distribution.

Verbal noun of populate, from M.L. populatus, p.p. of populare "to inhabit," from L. populus "people."

In the IE languages the concepts of "full, many, multitude" and "people, group, herd, flock" are related. In Pers. several variants of por "full, much, many" denote "group, population," as in Lori, Qâyeni bor "group, tribe, herd," Torbat-Heydariyeyi, Qomi borr "heap, bundle, group," Qomi borreh "group, assemblage of people," Pashtu parrak "flock, herd," Urdu para "flock, herd," Lârestâni baila "group, tribe," Tabari balik "herd, flock;" other examples from literary Pers. bâré "herd, flock," parré "a rank or file of soldiers, a circular disposition of troops." Therefore, porineš "population," verbal noun of porinidan "to populate," infinitive of porin "populous," from por "mutitude, many, full" + -in attribution suffix. Por, from Mid.Pers. purr "full;" O.Pers. paru- "much, many;" Av. par- "to fill," parav-, pauru-, pouru- "full, much, many;" PIE base *pelu- "full," from *pel- "to be full;" cf. Skt. puru- "much, abundant;" Gk. polus "many," plethos "great number, multitude;" O.E. full.

Population I star
  ستاره‌ی ِ پرینش ِ I   
setâre-ye-e porineš-e I

Fr.: étoiles de population I   

A member of a class of relatively young stars, containing a large fraction of → metals, found mainly in the disk of the Galaxy.

population; I, Roman number 1; → star.

Population II star
  ستاره‌ی ِ پرینش ِ II   
setâre-ye porineš-e II

Fr.: étoiles de population II   

A member of a population of relatively old stars, containing a small fraction of → metals, found mainly in the → halo of the Galaxy and in → globular clusters.

population; II, Roman number 2; → star.

Population III star
  ستاره‌ی ِ پرینش ِ III   
setâre-ye porineš-e III

Fr.: étoile de population III   

A member of the first generation of stars, formed out of pristine gas, enriched by → primordial nucleosynthesis alone. The material from which these stars formed consisted mostly of hydrogen and helium. Because neutral hydrogen clouds were free of dust, their cooling mechanism was drastically ineffective. As a result, these star forming clouds had a much higher temperature than in the present epoch, and their → Jeans mass was much higher. Therefore, these first generation of stars were principally massive, with a typical mass scale of order of about 100 Msun. Population III stars started forming about 300 million years after the → Big Bang at → redshifts between 50 and 6, when the Universe had between 1 and 5% of its present age. These stars were probably responsible for the → reionization of the Universe. Given their high mass, they lived only a few million years ending with either a → pair-instability supernova phase or a direct collapse to a → black hole. Population III stars thus initiated the chemical enrichment of the Universe and opened the way to more normal modes of star formation, namely → Population II. Some models predict a bimodal → initial mass function for the first stars, allowing also for solar mass stars. See also → extremely metal-poor star.

population; III, Roman number 3; → star.

population inversion
  واگردانی ِ پرینش، وارونش ِ ~   
vâgardâni-ye porineš, vâruneš-e ~

Fr.: inversion des populations   

In physics, specifically statistical mechanics, the state of an atomic or molecular system in which the number of members in an excited state is larger than those in lower energy states. → optical pumping; → inverted population.

population; → inversion.


Fr.: pore   

1) A small hole such as a space especially in a rock, soil, etc. → porous dust grain, → porosity.
2) A minute orifice in an animal or plant, as in the skin or a leaf.
3) Sun: A small → sunspot that does not have a → penumbra. Pores are up to about 2,500 km across and are lighter than a sunspot's → umbra. They appear and disappear at the surface of the Sun where sunspots are rarely formed, e.g. at low latitudes. Their lifetimes can be as short as 1/2 hour and as long as several days.

From L. porus "a pore," from Gk. poros "a pore," literally "passage, way," from PIE root *per- "to lead, pass over."

Lik, from Gilaki lik "hole," variants luk, luke, liuk, luxa, Tabari luk, li, Sangesari, Semnâni lu, Aftari lo.


Fr.: porosité   

1) General: A → dimensionless number characterizing a porous medium, expressed by the ratio of the volume occupied by the pores to the total volume of the medium.
2) Geology: The percentage volume of hollow spaces in a rock, sediment, or soil.
3) Dust grains: The quantity usually defined as: P = (Vv/Vt) = (1 - Vs/Vt), where Vv and Vs are the volumes of vacuum and of the solid matter making up the particle, and Vt is the total volume of the particle within some defined surface.

porous; → -ity.


Fr.: poreux   

Full of pores.

From M.Fr. poreux, from M.L. porosus, from L. porus "opening," → pore.

Porlik, from por "full; many," → full, + lik, → pore.

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)

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.

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").

  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.

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.

  نهش‌داد، نهشداد   

Fr.: positionnement   

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

Verbal noun of → position; → -ing.


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."

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