An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -sc Sag sam sat sca sca Sch Sco Sec sec sec seg sel sem sen set sha she sho sic sie sil sim sin sit sky slo sno sof sol sol sol sol sor sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sup sup sup sup sur sur syl syn sys > >>

Number of Results: 1347
secondary crater
  لاوک ِ دومان، کندال ِ ~   
lâvak-e dovomân, kandâl-e ~

Fr.: cratère secondaire   

A crater formed by the relatively low-velocity impact of fragments ejected from a large primary crater. Secondary craters tend to cluster in a ring around the primary crater.

secondary; → crater.

secondary eclipse
  گرفت ِ دومان   
gereft-e dovomân

Fr.: éclipse secondaire   

Of a transiting → exoplanet, the event and the interval of time during which the planet passes behind its host star. → primary eclipse.

secondary; → eclipse.

secondary electrons
  الکترون‌های ِ دومان   
elektronhâ-ye dovomân

Fr.: électrons secondaires   

Electrons ejected from the atoms of a material when bombarded with high energy electrons. Secondary electrons are produced when an incident electron excites an electron in the material and loses some of its energy in the process. The excited electron moves toward the surface of the sample undergoing elastic and inelastic collisions until it reaches the surface, where it can escape if it still has sufficient energy. The secondary electron yield depends on many factors, and is generally higher for high atomic number targets, and at higher angles of incidence.

secondary; → electron.

secondary emission
  گسیل ِ دومان   
gosil-e dovomân

Fr.: émission secondaire   

The emission of → secondary electrons from the surface of a material when an incident particle (often, charged particle such as electron or ion) impacts the material with sufficient energy.

secondary; → emission.

secondary mirror
  آینه‌ی ِ دومان   
âyene-ye dovomân

Fr.: miroir secondaire   

The second reflecting surface in a → reflecting telescope. It directs the light either out a side opening of the tube (→ Newtonian telescope) or back toward a → focal point behind and through the → primary mirror (→ Cassegrain telescope). The secondary is usually suspended in the beam and therefore obstructs part of the primary.

secondary; → mirror.

secondary rainbow
  رنگین‌کمان ِ دومان   
rangin-kamân-e dovomân

Fr.: arc-en-ciel secondaire   

A fainter rainbow appearing about 10° above the → primary rainbow, as viewed by the observer. The secondary rainbow is about twice as wide, and has its colors reversed.

secondary; → rainbow.

secondary star
  ستاره‌ی ِ دومان   
setâre-ye dovomân

Fr.: étoile secondaire   

In a → binary system, the star that revolves around the more massive → primary component.

secondary; → star.

râz (#)

Fr.: secret   

1) Something that is or is kept secret, hidden, or concealed; a → mystery.
2) Done, made, or conducted without the knowledge of others (

From L. secretus "set apart, withdrawn; hidden, concealed," p.p. of secernere "to set apart, part, divide; exclude," from se- "without, apart," properly "on one's own" + cernere "to separate," → crisis.

Râz, from Mid.Pers. râz "secret, mystery;" cognate with Mod.Pers. rastan/rah- "to escape, be liberated;" O.Pers. (+*aua-) avarad- "to leave, abandon;" cf. Skt. rah- "to be lost, be lonely," rahas- "loneliness, privacy; a secret, mystery" (Cheung 2007).

dabirxâné (#)

Fr.: secrétariat   

The officials or office entrusted with administrative duties, maintaining records, and overseeing or performing secretarial duties, especially for an international organization (

From Fr. secrétariat, from M.L. secretariatus, from secretarius, → secretary.

Dabirxâné, literally "house of secretaries," from dabir, → secretary, + xâné, → house.

dabir (#)

Fr.: secrétaire   

A person, usually an official, who is in charge of the records, correspondence, minutes of meetings, and related affairs of an organization, company, association, etc. (

M.E. secretarie "one trusted with private or secret matters; confidant," from M.L. secretarius "confidential officer, confidant, clerk, notary," from L. secretum "a secret, a hidden thing."

Dabir, from Mid.Pers. dipîr, contraction of dipîvar (Mid.Pers. dip, dīp "document;" dīb "letter"); from O.Pers., from Proto-Ir. *dipī-uara- "he who preserves the documents;" cf. O.Pers. dipī- "inscription" + *Huar- "to cover;" cf. Av. vār- "to cover, hide, protect."


Fr.: secrétaire général   

The head or chief administrative officer of a secretariat.

secretary; → general.

sekanj (#)

Fr.: section   

A part that is cut off or separated.
A distinct part or subdivision of anything. → cross section; → intersection

From M.Fr. section, from L. sectionem "a cutting, division," from secare "to cut;" PIE base *sek- "cut" (cf. O.C.S. seko, sesti "to cut," Lith. isekti "to engrave, carve;" O.S. segasna, O.E. sigðe "scythe;" O.E. secg "sword," seax "knife, short sword").

Sekanj "a scraping, shaving, cutting," cognate with Pers. šekast-, šekastan "to break;" Av. skand- "to break," Skt. khand- "to break," khanda- "piece;" Pers. dialect Tabari šag "a special razor used to make incisions in the walls of unripe opium poppies in order to extract the milky sap," may be related to PIE *sek- "cut," as above.

  ۱) دیریاز؛ ۲) گیانه، گیانی؛ گیان‌باور   
1) diryâz; 2) a), b) giyâné, giyâni; c) giyânbâvar

Fr.: 1) séculaire; 2) laïc   

1a) General: Going on from age to age; continuing through long ages.
1b) Astro.: Gradual or taking place over a long period. → secular acceleration; → secular change.
2a) (adj.) Worldly or material rather than spiritual.
2b) (adj.) Not overtly or specifically relating to religion or to a religious body.
2c) (adj. & n.) Relating to or advocating secularism; a layperson.

Secular from O.Fr. seculer, from L.L. sæcularis "of an age, occurring once in an age," from sæculum "age, span of time, generation, the spirit of the age."

1) Diryâz "long lasting, from dir "slowly, tardily; late" (Mid.Pers. dêr, variants dagr, drâz "long;" (Mod.Pers. derâz "long," variant Laki, Kurdi derež); O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" L. longus "long;" Gk. dolikhos "elongated;" O.H.G., Ger. lang; Goth. laggs "long;" PIE base *dlonghos- "long") + yâz present stem of yâzidan "to stretch out the arms; grow up" (Parthian Mid.Pers. y'd "to reach a goal, come to, stretch out;" Av. yat- to reach, take one's place," yaiiata "places," frā-iiatāt "has reached;" cf. Skt. yat- "to be in place, put in place, line up;" PIE base *iet- "to be in place").
2) Giyâné, giyâni from giyân, variant of Mod.Pers. jahân, keyhân, geyhân "world," giti "world, material world, time," Mid.Pers. gêhân "world," gêtig "the material world; wordly," Manichean Mid.Pers. gyh "world," gyh'n "worlds;" Av. gaē&thetaā- "being, world, matter, mankind," gaya- "life, manner of living", root gay- "to live" (present tense jiva-), O.Pers. gaiθā- "live-stock," cognate with Skt. jīv- "to live," jīva- "alive, living;" Gk. bios "life," L. vivus "living, alive," vita "life;" PIE base *gwei- "to live" (cf. O.E. cwic "alive;" O.C.S. zivo "to live;" Lith. gyvas "living, alive;" O.Ir. bethu "life," bith "age, life, world;" Welsh byd "world"). The Pers. words zistan "to live," zendé "alive," zendegi "life," and jân "vital spirit, soul; mind" belong to this family.

secular aberration
  بیراهش ِ دیریاز   
birâheš-e diryâz

Fr.: aberration séculaire   

The smallest component of the aberration of starlight which is caused by the motion of the solar system through space. → annual aberration; → diurnal aberration.

secular; → aberration.

secular acceleration
  شتاب ِ دیریاز   
šetâb-e diryâz

Fr.: accélération séculaire   

The apparent gradual increase in the → Moon's motion in its orbit, as measured relative to → mean solar time. Secular acceleration corresponds to an extremely gradual reduction in the speed of the → Earth's rotation. The slow-down of the Earth's spin comes mainly from → tidal frictions from the Moon. Historically, Edmond Halley (1656-1742) was the first to suggest that the Moon's mean rate of motion relative to the stars was gradually increasing. In 1693, Halley compared eclipses of recent, medieval, and classical Babylonian time, and discovered that the Moon's mean motion had been gradually increasing. Using Lunar Laser Ranging measurement, based on laser reflectors left by the Apollo astronauts on the Moon's surface (1969 to 1972), the secular acceleration is derived to be -25".4 ± 0".1 century 2 (Xu Huaguan et al., 1996, in Earth, Moon and Planets 73, 101). This corresponds to a linear increase of about 3.5 cm yr-1 in the mean Earth-Moon distance.

secular; → acceleration.

secular change
  دگرشد ِ دیریاز، دگرش ِ ~   
degaršod-e diryâz, degareš-e ~

Fr.: changement séculaire   

A continuous, non-periodic change in one of the attributes of the states of a system. Often, a change in an orbit due to dissipation of energy. See also → canonical change.

secular; → change.

secular instability
  ناپایداری ِ دیریاز   
nâpâydâri-ye diryâz

Fr.: instabilité séculaire   

Instability caused by a slow dissipation of energy.

secular; → instability.

secular parallax
  دیدگشت ِ دیریاز   
didgašt-e diryâz

Fr.: parallaxe séculaire   

The angle subtended at a star by a baseline that is the distance the Sun moves in a given interval of time with respect to the local standard of rest (4.09 AU per year).

secular; → parallax.

secular perturbation
  پرتورش ِ دیریاز   
partureš-e diryâz

Fr.: perturbation séculaire   

A variation of planetary orbital elements which is always in the same direction as time increases.

secular; → perturbation.

secular stability
  پایداری ِ دیریاز   
pâydâri-ye diryâz

Fr.: stabilité séculaire   

1) The condition in which the equilibrium configuration of a system is stable over long periods of time.
2) The condition of a star when it is stable against arbitrary adiabatic perturbations.

secular; → stability.

<< < -sc Sag sam sat sca sca Sch Sco Sec sec sec seg sel sem sen set sha she sho sic sie sil sim sin sit sky slo sno sof sol sol sol sol sor sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sup sup sup sup sur sur syl syn sys > >>