An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit cla clo clo clu Coa coe coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>

Number of Results: 13048 Search : far
permafrost
  ماندبشم   
mândbašm

Fr.: pergélisol   

Layer of soil or rock, at some depth beneath the surface, in which the temperature has been continuously below 0°C from a few to several thousands of years. It exists where summer heating fails to reach the base of the layer of frozen ground.

From perma(nent) + → frost.

Mândbašm, from mând, → permanent, + bašm, → frost.

permanent
  ماندگار   
mândegâr (#)

Fr.: permanent   

Lasting or remaining without essential change.

Permanent, from M.Fr. permanent, from L. permanentem "remaining," pr.p. of permanere "endure, continue, stay to the end," from per- "through" + manere "stay," cognate with Pers. mândan, as below; → gas.

permanent gas
  گاز ِ ماندگار   
gâz-e mândegâr

Fr.: gaz permanent   

Gas which cannot be liquefied by pressure alone; gas above its critical temperature.

permanent; → gas.

permanent magnet
  آهنربای ِ ماندگار   
âhanrobâ-ye mândegâr

Fr.: aimant permanent   

A piece of magnetic material which, having been → magnetized, retains a substantial proportion of its → magnetization indefinitely. In permanent magnets the magnetic field is generated by the internal structure of the material itself. Atoms and crystals constituting materials are made up of electrons and atomic nuclei. Both the nucleus and the electrons themselves act like little magnets. There is also a magnetic field generated by the orbits of the electrons as they move about the nucleus. So the magnetic fields of permanent magnets are the sums of the nuclear spins, the electron spins and the orbits of the electrons themselves. In many materials, the magnetic fields are pointing in all sorts of random directions and cancel each other out and there is no permanent magnetism. But in certain materials, called → ferromagnets, all the spins and the orbits of the electrons will line up, causing the materials to become magnetic. Many permanent magnets are created by exposing the magnetic material to a very strong external magnetic field. Once the external magnetic field is removed, the treated magnetic material is now converted into a permanent magnet. Overheating a permanent magnet causes the magnet's atoms to vibrate violently and disrupt the alignment of the atomic domains and their dipoles. Once cooled, the domains will not realign as before on their own and will structurally become a temporary magnet (MagLab Dictionary).

permanent; → magnet.

permanent memory
  برم ِ ماندگار   
barm-e mândegâr

Fr.: mémoire permanente   

Storage capacity which does not depend on a continuous supply of power, e.g. disks, magnetic tapes, etc.

permanent; → memory.

permeability
  تراوایی   
tarâvâyi (#)

Fr.: perméabilité   

The degree of → magnetization of a material that responds linearly to an applied magnetic field. → magnetic permeability.

From permeable, from L. permeabilis "that can be passed through, passable," from L. permeare "to pass through," from per- "through" + meare "to pass," from PIE base *mei- "to change; to go, move."

Tarâvâyi quality noun of tarâvâ "permeable," from tarâvidan "to exude, trickle, ooze; to drop," probably from Proto-Iranian *tra-vaxš-. The first component *tra- "across, over, beyond," → trans-. The second component *vaxš-, cf. Av. uxš-/vaxš- "to sprinkle," present tense stem uxš-; cf. Skt. uks- "to sprinkle, moisten," uksati "spinkles, wets;" Gk. hygros "wet, moist, fluid;" L. uvidus "watery, humid, damp." Tarâvidan may be a back formation from *tarâvaš.

permission
  پرزامش   
parzâmeš

Fr.: permission   

The act of permitting. Authorization granted to do something.

verbal noun of → permit; → -tion.

permit
  پرزامیدن   
parzâmidan

Fr.: permettre   

To allow to be done or occur.

From M.Fr. permetre, from L. permittere "give up, allow, allow to pass through," from per- "through;" (from PIE base *per- "through, across, beyond;" cf. Gk. peri "around, about, beyond;" O.Pers. pariy "around, about," Av. pairi "around, over;" Skt. pari; Indo-Iranian *pari- "around;" Mod.Pers. par-, pirâ- "around, about") + mittere "let go, send."

Parzâmidan, literally "to allow to go through," infinitive of parzâm, from par- "through," from O.Pers. pariy "around, about," Av. pairi "around, over," cognet with L. per-, as above + zâm stem of Mid.Pers. zâmenidan "to let go, lead, send," Mod.Pers. gâm "step, pace," âmadan "to come;" O.Pers./Av. gam- "to come; to go," Av. jamaiti "goes;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step," L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come," E. come; PIE base *gwem- "to go, come."

permitted
  پرزامیده   
parzâmidé

Fr.: permis   

Allowed. → permitted line; → permitted transition.

Past participle of → permit.

permitted line
  خط ِ پرزامیده   
xatt-e parzâmidé

Fr.: raie permise   

An ordinary spectral line emitted by atoms undergoing energy transitions that are allowed by the selection rules of quantum mechanics. → forbidden lines.

permitted; → line.

permitted transition
  گذرش ِ پرزامیده   
gozareš-e parzâmidé

Fr.: transition permise   

A transition between two quantum mechanical states that does not violate the quantum mechanical selection rules.

permitted; → transition.

permittivity
  پرزامندگی   
parzâmandegi

Fr.: permittivité   

A measure of the ability of a material to transmit (or "permit") an electric field. Permittivity is defined as the ratio of the flux density produced by an electric field in a given dielectric to the flux density produced by that field in a vacuum. In → SI units, permittivity is measured in → farads per meter. The constant ε0 is known as the permittivity of free space; its value is about 8.854 x 10-12 F/m.

State or quality noun from → permit.

permutation
  پرموتش، جایگشت   
permuteš, jâygašt

Fr.: permutation   

Math.: A rearrangement of the elements of a set in a particular order. The number of permutations of n objects is equal to n! (→ factorial n). For example, there are 24 permutations of letters A, B, C, and D (4! = 1 × 2 × 3 × 4). The number of permutations of n objects taken r at a time is denoted by nPr and equals n! / (n - r)!. For example, the number of permutation of A, B, C, and D taken two at a time is 12. If n objects are of k different kinds, with r1 alike of one kind, permutations of n objects equals n! / r1! r2! ... rk!, where r1 + r2 + ... rk = n.

Verbal noun of → permute.

Permuteš, verbal noun of → permute.
Jâygašt , from "place" (from Mid.Pers. giyag "place;" O.Pers. ā-vahana- "place, village;" Av. vah- "to dwell, stay," vanhaiti "he dwells, stays;" Skt. vásati "he dwells;" Gk. aesa (nukta) "to pass (the night);" Ossetic wat "room; bed; place;" Tokharian B wäs- "to stay, wait;" PIE base ues- "to stay, live, spend the night") + gašt past tense of gaštan, gardidan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend").

permute
  پرموتیدن   
permutidan

Fr.: permuter   

M.E., from L. permutare "to change throughout," from per- "through" + mutare "to change," from PIE base *mei- "to change, go, move;" cf. Av. miθô "inverted, false," miθaoxta- "wrong spoken;" Skt. methati "changes, alternates, joins, meets," mith- "to alternate, meet," mithás "opposite, in opposition;" L. meare "to go, pass," mutuus "done in exchange;" Goth. maidjan "to change;" E. prefix mis- (in mistake).

Permutidan, from permute, as above.

perpendicular
  پالار   
pâlâr

Fr.: perpendiculaire   

A line or plane at right angles to another line or plane. Two curves are said to be perpendicular if their tangent lines are mutually perpendicular. → normal; → vertical

From M.E. perpendiculer(e), from O.Fr. perpendiculiere, from L. perpendicularis "vertical, as a plumb line," from perpendiculum "plumb line," from perpendere "balance carefully," from per- "thoroughly" + pendere "to weigh, to hang."

Pâlâr "pillar, column, main beam."

perpendicular axis theorem
  فربین ِ آسه‌ها‌ی ِ پالار   
farbin-e âsehâ-ye pâlâr

Fr.: théorème des axes perpendiculaires   

The → moment of inertia of a plane object (→ lamina) about an axis perpendicular to the plane is equal to the sum of the moments of inertia about any two perpendicular axes in the plane. Thus if x and y axes are in the plane, Iz = Ix + Iy.

perpendicular; → axis; → theorem.

perpetual
  همیشگی   
hamišegi (#)

Fr.: perpétuel   

Lasting an indefinitely long time; eternal; permanent. → perpetual motion; → perpetual calendar.

M.E. perpetuall, from O.Fr. perpetuel, from L. perpetualis "permanent," from perpetuus "continuous, universal," from perpetis, genitive of Old L. perpes "lasting;"

Hamišegi from hamišé "always;" Mid.Pers. hamišag, from anôšag "immortal," from Av. an-aoša-, from negation prefix → an- + aošah- "death; ruin; corruption" (Mid.Pers. hôš "death;" Mod.Pers. hôš, huš "death; mind; intellect"); cf. derivatives Sogd. nôšé "immortal," nôšak "always;" Mod.Pers. nôš, nuš "the water of immortality; sweet; honey."

perpetual calendar
  گاهشمار ِ همیشگی   
gâhšomâr-e hamišegi

Fr.: calendrier perpétuel   

A chart or mechanical device that indicates the day of the week for any given date over a period of many years.

perpetual; → calendar.

perpetual motion
  جنبش ِ همیشگی   
jonbeš-e hamišegi

Fr.: mouvement perpétuel   

The motion of a hypothetical machine which, once set in motion, will go on for ever without any losses due to → friction or other forms of → dissipation of energy and without receiving any external energy.

perpetual; → motion.

Perseids
  پرسءوسیان   
Perseusiyân

Fr.: Perséides   

A → meteor shower, one of the three most active of the year, which occurs between July 25 and August 20 with the greatest activity between August 8 and 14, peaking about August 12. The Perseids appear as the Earth's orbit around the → Sun crosses the dusty tail of the comet → Swift-Tuttle, as first explained by Giovanni Schiaparelli (1835-1910), an Italian astronomer. Usually about 50 meteors can be seen per hour, but in outburst years (such as in 2016) the rate can be between 150-200 meteors an hour.

Perseus + -ids.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit cla clo clo clu Coa coe coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>