An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

<< < -es -it -sc 201 951 abe abs abs aca acc acc aco act ada adh ado aer aft air Alf alg alk alp Alt alt amb ana And ang ani ann ant ant ant apo app app Apu arc arg Arn art ass ast ast ast atm ato att aur aut avo azi bac bal bar bar bat Bea Bel bet bia big bin bio Bir bla bla blo Blu bol Boo bou box bre Bri bro bur cal cal Can cap car Car cat cau cel cen cen cha Cha cha che Chi chr cir cir civ cla clo clo CMB 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 coo cor cor cor Cos cos cos cou cou cra cri cro cry cul cur cyc D l dar dat day dea dec dec dec def def deg Del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra Dsc dus dwa dyn Dys Ear ecc eco edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ eru eth Eur eve exa exc exe exi exo exp ext ext ext fab fai Fan fea fem fer fie fil fir fir fla fli flu foc for for for fra fre fre fri fun fuz gal gal gal Gam gau Gau gen geo geo geo geo Gib glo gov gra gra gra gra gre gro Gui H-a hal Ham har Hay hea hei hel Hel her het hie hig hoa hom hor hot Hub Hug hur hyd hyd hyl 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 inv ion iro Isl iso iso Jab jet Jov Jup Kar Kep kil Kip Kra Lag Lam Lan Lar las law lea Leg Leo lev lig lim lin lin lin lit loc loc log Lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal map mas mas mat Mau mea mea med Men mer Mes Met met mic mic Mie mil min Mir mix mod mol mom Moo mor mov mul mur n-b nan nat nea neg Ner neu new New NGC noc nom non non nor nor nuc nuc nul nut obj obl obs occ oct off old one ope opp opt opt orb ord org Ori osc oth ove Owl P-s Pal par par par par Pas pat pec pen per per per per per Pha pha pho pho pho phy pie pix Pla pla pla pla Pli Poi pol pol pol pol por pos pos pow pre pre pre pre pri pri pri pro pro pro pro pro pro pro pub pul pyc qua qua qua qua qui rad rad rad rad rad rad rai 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 rur S5- Sal sat sca sca Sch sci Scu sec sec sed sel sel sem seq set sha she sho sid sie sil sim sin sit sky slo sno sod sol sol sol sol son sou spa spa spe spe spe spe sph spi spo squ sta sta sta sta ste ste ste Sti sto str str sub sub sub sul sup sup sup sup sur sur syl syn sys tal Tay tel ten ter tex the the the the Tho thr tid tim Tit too Tor tra tra Tra tra Tra tri Tri tru tub tur two Typ ult ult unc uni uni uni upl ura uti val var vec vel ver Ver vie vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>

Number of Results: 13176 Search : in
perihelion advance
  پیشرفت ِ پیراهور   
pišraft-e pirâhur

Fr.: avance du périhélie   

advance of perihelion.

advance of perihelion.

perihelion distance
  اپست ِ پیراهوری   
apest-e pirâhuri

Fr.: distance au périhélie   

The distance between the → Sun and an → object in orbit around it when they are at their closest approach.

perihelion; → distance.

perihelion precession
  پیشایانِ پیراهوری   
pišÃ¢yân-e pirâhuri

Fr.: précession du périhélie   

advance of perihelion.

perihelion; → precession.

perijove
  پیراهرمز   
pirâhormoz

Fr.: périjove   

The → point in the → orbit of a → satellite of → Jupiter that is nearest to Jupiter's center. → apojove.

peri- + jove, from L. Jovius "Jupiter," → Jovian.

peril
  سیج   
sij (#)

Fr.: péril   

1) Exposure to injury, loss, or destruction; grave risk; jeopardy; danger.
2) Something that causes or may cause injury, loss, or destruction (Dictionary.com).

M.E., from O.Fr. peril "danger, risk," from L. periculum "an attempt, trial; risk, danger," related to experiri "to try," cognate with Gk. peria "trial, attempt," empeiros "experienced;" O.Ir. aire "vigilance;" Goth. ferja "watcher;" O.E. fær "danger; fear."

Sij "trouble;" Mid.Pers. sêj "danger, trouble," sêjômand "dangerous;" Av. iθyejah- "trouble, danger," iθyejahvant- "full of danger, hazardous;" cf. Skt. tyajas- "difficulty, danger."

perilune
  پیراماه   
pirâmâh

Fr.: périlune   

The point in a lunar orbit that is nearest to the moon. Same as → pericynthion.

From → peri- + lune, from L. luna "moon;" → lunar.

Pirâmâh, → apocynthion.

perimeter
  پیرامون   
pirâmun (#)

Fr.: périmètre   

The total outer boundary of a two-dimensional figure.

peri- + → -meter.

period
  دوره   
dowré (#)

Fr.: période   

Physics: The duration of one complete cycle of an oscillation; the reciprocal of the frequency.
Astro.: The amount of time an astronomical body takes to complete an orbit.

From M.E. periode, from M.Fr., from M.L. periodus "recurring portion, cycle," from L. periodus "a complete sentence," from Gk. periodos "rounded sentence, cycle, circuit, period of time," literally "going around," from → peri- "around" + hodos "way, journey;" cognate with L. cedere "to go, yield."

Dowré, from dowr, from Ar. daur "age, time; revolution."

period derivative
  واخنه‌ی ِ دوره   
vâxane-ye dowré

Fr.: dérivée de la période   

The rate at which the rotation period of a → pulsar changes over time. This quantity, dP/dT, can range from as small as 0.05 picoseconds per year (1.5 x 10-21 seconds per second) to as large as about 10 milliseconds per year (4.2 x 10-10 seconds per second). For the → Crab pulsar, the period derivative is 4.2 x 10-13 s s-1, implying a decrease in the star's → rotation energy of about 4.5 x 1038 erg s-1. Period derivative is a very important parameter for the determination of the pulsar age.

period; → derivative.

period-luminosity relation
  باز‌آنش ِ دوره-تابندگی   
bâzâneš-e dowré-tâbandegi

Fr.: relation période-luminosité   

A → correlation between the periods and luminosities of → Cepheid variable stars: Cepheids with longer periods are intrinsically more luminous than those with shorter periods. The relation was discovered by Henrietta Leavitt in 1912 when studying Cepheids in the → Small Magellanic Cloud. Once the period of a Cepheid variable is determined from observations, the period-luminosity relation can be used to derive its luminosity. Since luminosity is a function of → distance, the distance can then be calculated with the luminosity. The period-luminosity relation is an invaluable tool for the measurements of distances out to the nearest galaxies and thus for studying the structure of our own Galaxy and of the Universe.

period; → luminosity; → relation.

period-mean density relation
  باز‌آنش ِ دوره-چگالی ِ میانگین   
bâzâneš-e dowré-cagâli-ye miyângin

Fr.: relation période-densité moyenne   

A relation that gives a rough estimate of the oscillation period of a → pulsating star as a function of its mean density. This relation is obtained by considering how long it would take a sound wave to travel across the diameter of a model star: Π ≅ (3π/2γGρ)1/2, where ρ is the mean density, γ the ratio of → specific heats (Cp/Cv), and G the → gravitational constant. This relation shows that the pulsation period of a star is inversely proportional to the square root of its mean density. And this is the reason why the pulsation periods decrease along the → instability strip from the luminous, very tenuous → supergiants to the faint, very dense → white dwarfs.

period; → mean; → density; → relation.

periodic
  دوره‌ای   
dowreyi (#)

Fr.: périodique   

Recurring at regular intervals of time.

Adjective of → period.

periodic comet
  دنباله‌دار ِ دوره‌ای   
dombâledâr-e dowreyi

Fr.: comète périodique   

A comet with a period of less than 200 years. Also called short-period comet.

periodic; → comet.

periodic function
  کریای ِ دوره‌ای   
karyâ-ye dowreyi

Fr.: fonction périodique   

A function f(x) if for all x, f(x + P) = f(x), where P is a positive constant. The least value of P > 0 is called the period of f(x).

periodic; → function.

periodic motion
  جنبش ِ دوره‌ای   
jonbeš-e dowreyi

Fr.: mouvement périodique   

Any motion that recurs in identical forms at equal intervals of time.

periodic; → motion.

periodic system
  راژمان ِ دوره‌ای   
râžmân-e dowreyi

Fr.: système périodique   

Arrangement of the → chemical elements in the → periodic table.

periodic; → system.

periodic table
  جدول ِ دوره‌ای   
jadval-e dowreyi (#)

Fr.: tableau périodique   

An arrangement of the → chemical elements in order of their → atomic numbers in such a way as to demonstrate periodic similarities and trends in physical and chemical properties. Elements with similar properties are arranged in the same column (called a group), and elements with the same number of → valence electrons, or number of electrons in the outer shell, are arranged in the same row (called a period). Under the latest recommendations from IUPAC (the International Union of Pure and Applied Chemistry), the groups are labelled 1 to 18 from left to right (1988, Pure and Applied Chemistry 60, 431). Also called Mendeleev's table.
The periodic table was introduced by Dmitri Ivanovich Mendeleev (1834-1907) in 1869, who originally arranged them in order of their → atomic weights. Using the table, it was possible for Mendeleev to correct some of the atomic weights (e.g. that of beryllium) and to predict the properties of a number of elements yet to be discovered (e.g. gallium, scandium, and germanium). The British physicist Frederick Soddy (1877-1956) showed that the loss of an → alpha particle reduces the nuclear charge by two and hence lowers the atomic number by two and the position of the element in the periodic table by two groups.

periodic; → table.

periodic term
  ترم ِ دوره‌ای   
tarm-e dowre-yi

Fr.: terme périodique   

In perturbation theory used in celestial mechanics, a term that indicates a bounded disturbance which recurs regularly. → secular term.

periodic; → term.

periodic wave
  موج ِ دوره‌ای   
mowj-e dowre-yi

Fr.: onde périodique   

An oscillatory motion in which each point is repeatedly displaced at equal time intervals.

periodic + → wave.

periodical
  دوره‌ای   
dowreyi (#)

Fr.: périodique   

Same as → periodic.

periodic; → -al.

<< < -es -it -sc 201 951 abe abs abs aca acc acc aco act ada adh ado aer aft air Alf alg alk alp Alt alt amb ana And ang ani ann ant ant ant apo app app Apu arc arg Arn art ass ast ast ast atm ato att aur aut avo azi bac bal bar bar bat Bea Bel bet bia big bin bio Bir bla bla blo Blu bol Boo bou box bre Bri bro bur cal cal Can cap car Car cat cau cel cen cen cha Cha cha che Chi chr cir cir civ cla clo clo CMB 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 coo cor cor cor Cos cos cos cou cou cra cri cro cry cul cur cyc D l dar dat day dea dec dec dec def def deg Del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis diu dog Dop dou Dra Dsc dus dwa dyn Dys Ear ecc eco edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ eru eth Eur eve exa exc exe exi exo exp ext ext ext fab fai Fan fea fem fer fie fil fir fir fla fli flu foc for for for fra fre fre fri fun fuz gal gal gal Gam gau Gau gen geo geo geo geo Gib glo gov gra gra gra gra gre gro Gui H-a hal Ham har Hay hea hei hel Hel her het hie hig hoa hom hor hot Hub Hug hur hyd hyd hyl 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 inv ion iro Isl iso iso Jab jet Jov Jup Kar Kep kil Kip Kra Lag Lam Lan Lar las law lea Leg Leo lev lig lim lin lin lin lit loc loc log Lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal map mas mas mat Mau mea mea med Men mer Mes Met met mic mic Mie mil min Mir mix mod mol mom Moo mor mov mul mur n-b nan nat nea neg Ner neu new New NGC noc nom non non nor nor nuc nuc nul nut obj obl obs occ oct off old one ope opp opt opt orb ord org Ori osc oth ove Owl P-s Pal par par par par Pas pat pec pen per per per per per Pha pha pho pho pho phy pie pix Pla pla pla pla Pli Poi pol pol pol pol por pos pos pow pre pre pre pre pri pri pri pro pro pro pro pro pro pro pub pul pyc qua qua qua qua qui rad rad rad rad rad rad rai 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 rur S5- Sal sat sca sca Sch sci Scu sec sec sed sel sel sem seq set sha she sho sid sie sil sim sin sit sky slo sno sod sol sol sol sol son sou spa spa spe spe spe spe sph spi spo squ sta sta sta sta ste ste ste Sti sto str str sub sub sub sul sup sup sup sup sur sur syl syn sys tal Tay tel ten ter tex the the the the Tho thr tid tim Tit too Tor tra tra Tra tra Tra tri Tri tru tub tur two Typ ult ult unc uni uni uni upl ura uti val var vec vel ver Ver vie vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>