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: 1054
pascal (Pa)
  پاسکال   
pâskâl (#)

Fr.: pascal   

The → SI unit of → pressure, that of one → newton per → square → meter. Since 1 Pa is a small pressure, hPa (→ hectopascals) are more widely used. 1 Pa = 10 dyn cm-2, = 1.02 x 10-5 kgf cm-2 = 10-5 bars = 9.87 x 10-6 atm = 7.50 x 10-3 torr (mm Hg).

In honor of Blaise Pascal (1623-1662), French mathematician, physicist, and religious philosopher for his contribution in the study of hydrodynamics and hydrostatics, in particular establishing the principle of the barometer.

Pascal's barrel experiment
  آزمایش ِ چلیک ِ پاسکال   
âzmâyeš-e celik-e Pascal

Fr.: expérience du tonneau de Pascal   

An experiment carried out by Blaise Pascal in 1646 to demonstrate the hydraulic pressure. A long and narrow vertical pipe was connected to the content of a closed wooden barrel already full of water. He poured a small quantity of water into the pipe, whereby the height of the fluid within the pipe sharply increased. Due to the increase in hydrostatic pressure and → Pascal's law, the barrel could leak and even burst.

pascal (Pa); M.E. barel, from M.Fr. baril, O.Fr. barril; → experiment

Pascal's law
  قانون ِ پاسکال   
qânun-e pâskâl (#)

Fr.: loi de Pascal   

A change in the pressure of an enclosed incompressible fluid is conveyed undiminished to every part of the fluid and to the surfaces of its container.

Named after Blaise Pascal (1623-1662), French mathematician, physicist, and religious philosopher for his contribution in the study of hydrodynamics and hydrostatics, in particular establishing the principle of the barometer.

Pascal's triangle
  سه‌بر ِ پاسکال   
sebar-e Pascal

Fr.: triangle de Pascal   

An array of numbers in the shape of a triangle, having a 1 at the top and also at the ends of each row. Each number is obtained by summing the two adjacent numbers to it in the preceding row. Each row is a set of → binomial coefficients. In the expansion of (x + y)n, the coefficients of x and y are given by the n-th row of Pascal's traingle.

pascal; → triangle.

Paschen series
  سری ِ پاشن   
seri-ye Paschen (#)

Fr.: série de Paschen   

The spectral series associated with the third energy level of the hydrogen atom. The series lies in the infrared, with Pα at 18,751 Å, and Paschen limit at 8204 Å.

In honor of Friedrich Paschen (1865-1947), German physicist; → series.

Paschen-Back effect
  ا ُسکر ِ پاشن-بک   
oskar-e Paschen-Back

Fr.: effet Paschen-Back   

An effect on spectral lines obtained when the light source is located in a strong magnetic field. The strong field disrupts the coupling between the orbital and spin angular momenta, resulting in a different pattern of splitting.

Named for the German physicists Friedrich Paschen (1865-1947) and Ernst E. A. Back (1881-1959); → effect.

Pasiphae
  پسیفاءه   
Pâsifâé

Fr.: Pasiphaé   

The fifteenth of Jupiter's known satellites, orbiting at 23,660,000 km from Jupiter; also known as Jupiter VIII. Its diameter is 36 km and orbital period 744 days.

In Gk. mythology, Pasiphae was the wife of Minos and mother, by a white bull, of the Minotaur.

passage
  گذر   
gozar (#)

Fr.: passage   

An act or instance of passing from one place, condition, etc., to another; transit. Same as → transit.

M.E, from O.Fr. passage, from passer "to go by;" originally "a road, passage."

Gozar "passage, transit, passing," from gozaštan "to pass, cross, transit," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" (O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over;" → trans-.

passband
  گذرباند   
gozar-bând

Fr.: bande passante   

The range of wavelengths that are transmitted by a filter. Same as → band-pass.

Pass from O.Fr. passer, from V.L. *passare "to step, walk, pass," from L. passus "step, pace;" cf. Pers. "foot," pey "step;" → band.

Gozar "passage, transit, passing," from gozaštan "to pass, cross, transit," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" ( O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over"); bând, → band.

passive
  اکار   
akâr

Fr.: passif   

Tending not to participate actively; not working or operating.

From L. passivus "submissive; capable of feeling or suffering," from passus, p.p. of pati "to experience, undergo, suffer."

Akâr "not working, not doing," from → a- negation prefix + kâr "work," varaint of kar, present stem of kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make").

passive cloud
  ابر ِ اکار   
abr-e akâr

Fr.: nuage passif   

A cumulus cloud that is no longer dynamically connected with the atmospheric boundary layer via updrafts or downdrafts.

passive; → cloud.

passive component
  همنه‌ی ِ اکار   
hamne-y akâr

Fr.: composante passive   

An electronic component which contains no source of power, in contrast to active components.

passive; → component.

passive galaxy
  کهکشان ِ اکار   
kahkešân-e akâr

Fr.: galaxie passive   

A galaxy lacking optical emission-line activity (e.g., [O II], Hα, [O III]) and showing only stellar absorption lines (e.g., the 4000 Å → calcium break, Mg I, Na I). Also called passively evolving galaxy.

passive; → galaxy.

passive system
  راژمان ِ اکار   
râžmân-e akâr

Fr.: système passif   

An electronic system which emits no energy, and is not detectable.

passive; → system.

passively evolving galaxy
  کهکشان با فرگشت ِ اکار   
kahkešân bâ fargašt-e akâr

Fr.: galaxie en évolution passive   

Same as → passive galaxy.

passive; → evolve; → galaxy.

password
  گذرواژ   
gozarvâž

Fr.: mot de passe   

An arbitrary string of characters chosen by a user or system administrator and used to authenticate the user when he attempts to log on, in order to prevent unauthorised access to his account (foldoc.org).

Pass, → passage; → word.

past
  گذشته   
gozašté (#)

Fr.: passé   

Of, having existed in, or having occurred during a time previous to the present; bygone (Dictionary.com).

M.E.; variant spelling of passed, p.p. of pass, from O.Fr. passer, from V.L. *passare "to step, walk, pass," from L. passus "step, pace;" cf. Pers. "foot," pey "step," → foot.

Gozašté, p.p. of gozaštan "to pass," → passage.

past participle
  پارگرته‌ی ِ گذشته   
pârgerte-ye gozašté

Fr.: participe passé   

A → participle that indicates a completed action or state.

past; → participle.

patch
  پچ   
pac (#)

Fr.: pièce   

1) A small piece of material used to mend a tear or break, to cover a hole, or to strengthen a weak place.
2) A piece of material used to cover or protect a wound, an injured part, etc.
3) A small piece, scrap, or area of anything (Dictionary.com). → bald patch; → patchy turbulence.

M.E. pacche; of uncertain origin.

Pac, from Bašgaridi (Giroft) pac "patch; fragment," probably from *parka-, from *par- "piece" + diminutive/relation suffix -ka; cf. pâré "piece, part, portion;" parré "portion, segment (of an orange);" pargâlé "piece, portion; patch;" Kermâni pariké "portion, half;" Tabari perik "minute quantity, particle;" Lârestâni pakva "patch;" Borujerdi parru "patch;" (Fin Bandar Abbâs) park "patch;" (Tâti) pajina "patch, darn;" → part.

patchy turbulence
  آشوبناکی ِ پچی، ~ تکه‌تکه   
âšubnâki-te paci, ~ tekke-tekké

Fr.: turbulence parcellaire   

A → turbulence that is not continuous in space, but is separated by regions of stability and → laminar flow.

Patchy adj. of → patch; → turbulence.

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