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
centrifugal
  مرکزگریز   
markaz-goriz (#)

Fr.: centrifuge   

Acting or moving in a direction away from the axis of rotation or the center of a circle along which a body is moving.

From Mod.L., coined 1687 by Sir Isaac Newton from L. centri-, combining form of centrum, → center, + fugere "to run away, flee."

Markaz-goriz, from markaz, → center, + goriz "running away," from gorixtan, gorizidan "to run away," Mid.Pers. virextan, proto-Iranian *vi-raik, from vi- "apart, asunder" + *raik, Av. raek- "to leave, set free, let off," Mid./Mod.Pers. reg/rig (in mordé-rig "inheritance," Skt. ric- "to leave," rinakti "gives up, evacuates," Gk. leipein "to leave," L. linquere "to leave," from PIE *linkw-, from *leikw- "to leave behind" (cf. Goth. leihvan, O.E. lænan "to lend;" O.H.G. lihan "to borrow;" O.N. lan "loan").

centrifugal acceleration
  شتاب ِ مرکزگریز   
šetâb-e markaz-goriz (#)

Fr.: accélération centrifuge   

Of a point rotating in a circle round a central point, the outward acceleration away from the rotation axis. It corresponds to → centrifugal force. The centrifugal acceleration is given by ω x ω x r, or v2/r, where ω is → angular velocity, r the distance to the rotating axis, and v the → tangential velocity. The centrifugal and → centripetal accelerations are equal and opposite.

centrifugal; → acceleration.

centrifugal force
  نیروی ِ مرکزگریز   
niru-ye markaz-goriz (#)

Fr.: force centrifuge   

A force in a rotating reference frame directed outward from the axis of rotation.

centrifugal; → force.

centripetal
  مرکزگرا   
markaz-gerâ

Fr.: centripète   

Acting or moving toward a → center or → axis. → centripetal acceleration, → centripetal force.

From Mod.L., coined 1687 by Sir Isaac Newton from L. centri- combining form of centrum "center" + petere "to fall, rush out;" cf. Av. pat- " to fly, fall, rush," Skt. patati "he flies, falls," Mid.Pers. patet "falls," opastan "to fall," Mod.Pers. oftâdan "to fall;" Gk. piptein "to fall," petomai "I fly;" PIE base *pet- "to fly, to rush."

Markaz-gerâ, from markaz, → center, + gerâ "inclining," from gerâyidan "to incline toward;" Mid.Pers. grâyitan, → diverge.

centripetal acceleration
  شتاب ِ مرکزگرا   
šetâb-e markaz-gerâ (#)

Fr.: accélération centripète   

The rate of change of the → tangential velocity of a body moving along a circular path. The direction of centripetal acceleration is always inward along the → radius vector of the → circular motion. The magnitude of the centripetal acceleration is related to the → tangential velocity (v) and → angular velocity (ω) as follows: ac = v2/r = rω2. According to → Newton's second law, an object undergoing centripetal acceleration is experiencing a → centripetal force.

centripetal; → acceleration.

centripetal force
  نیروی ِ مرکزگرا   
niru-ye markaz-gerâ (#)

Fr.: force centripète   

The force exerted on an object in → circular motion which is directed toward the center and keeps the body in motion. Centripetal force produces → centripetal acceleration, according to → Newton's second law: Fc = mac. Its direction is always inward along the → radius vector, and its magnitude is given by: Fc= mac = mvt2/r = mω2r.

centripetal; → force.

centroid
  مرکزوار   
markazvâr (#)

Fr.: centroïde   

1) Same as → center of gravity, → center of inertia, → center of mass, and → barycenter.
2) In a triangle, the point where the three medians converge.

center + → -oid.

Cepheid
  کفیءوسی   
Kefeusi

Fr.: céphéide   

A class of luminous, → yellow supergiants that are pulsating variables and whose period of variation is a function of their → luminosity. These stars expand and contract at extremely regular periods, in the range 1-50 days. Their highest brightness and surface temperature occur when their expansion velocity is greatest. Similarly, their minima in brightness and temperature occur when they are in the contraction phase. The longer the period, the more luminous the star. The process that drives the pulsation of → Cepheid variables is the → kappa mechanism. In fact, Cepheids provide one of the most powerful tools for measuring distances to other galaxies (→ period-luminosity relation). However, this method is limited to the distance of the → Virgo cluster of galaxies (15-20 → Mpc) even with the → HST or the largest ground-based telescopes. One particularly special Cepheid is the North Star, → Polaris. See also → RR Lyrae star.

Named after the prototype → Delta Cephei discovered by John Goodricke in 1784. → Cepheus.

Cepheid variable
  ورتنده‌ی ِ کفیءوسی   
vartande-ye Kefeusi

Fr.: variable Céphée   

A → variable star belonging to the class of → Cepheids.

Cepheid; → variable.

Cepheus
  کفیءوس   
Kefeus

Fr.: Céphée   

A → constellation in the Northern Hemisphere lying next to → Cassiopeia. It contains several pulsating variable stars, including the prototype → Cepheid variable Delta Cephei. Abbreviation: Cep, genitive: Cephei.

In Gk. mythology, Cepheus, king of Ethiopia, who was married to the beautiful → Cassiopeia, and was also father of princess → Andromeda.

Kefeus, from Gk. Cepheus. Arabicizd form qifâvus (قیفاووس).

Ceres
  سرس   
Seres (#)

Fr.: Cérès   

Once qualified as the largest known → asteroid, Ceres is now classified as a → dwarf planet (2006 IAU General Assembly). It is approximately 950 km across, and resides with tens of thousands of asteroids in the main → asteroid belt; it is the largest body of the belt. Its mass is 9.4 × 1020 kg, its → rotation period 9.074 hours, its → orbital period 4.60 years, and its → semi-major axis 2.767 AU. NASA's → Dawn spacecraft, which was placed in orbit around Ceres in 2015, has mapped its surface in great detail from a distance. Dawn caught sight of bright spots that soon resolved into more than 130 bright patches, most of them tied to craters. The most prominent of these spots lie inside the crater → Occator. The patches turned out to be carbonate salts, which only form in the presence of water. Since water skips to gas almost immediately on the dwarf planet's surface, the discovery of carbonates suggested that there was liquid beneath the dwarf planet's crust. Aside from craters, the only outstanding feature On Ceres is a single mountain, Ahuna Mons. It formed about 250 million years ago when plumes of saltwater and mud rose and erupted from within Ceres.

Ceres in Roman mythology was the goddess of growing plants and of motherly love. She was equivalent to Demeter in Gk. mythology.

CERN
     
CERN

Fr.: Centre Européen pour la Recherche Nucléaire (CERN)   

European Organization for Nuclear Research, founded in 1954, and located on the Franco-Swiss border near Geneva, Switzerland. CERN is one of the world's largest centres for scientific research. At CERN, the world's largest and most complex scientific instruments are used to study the basic constituents of matter, i.e. the → elementary particles. The instruments used at CERN are particle → accelerators and → detectors. Currently it has 20 Member States.

CERN, acronym of the organization's original name Centre Européen pour la Recherche Nucléaire.

Cerro Tololo Inter-American Observatory (CTIO)
  نپاهشگاه ِ اندر-آمریکایی ِ کوه ِ تولولو   
Nepâhešgâh-e andar-Âmrikâyi-ye Kuh-e Tololo

Fr.: Observatoire inter-américain du Cerro Tololo   

A complex of astronomical telescopes and instruments located approximately 80 km to the East of La Serena, Chile, at an altitude of 2,200 m. CTIO headquarters are located in La Serena, Chile, about 480 km north of Santiago. The principal telescopes on site are the 4-m Victor M. Blanco Telescope and the 4.1-m Southern Astrophysical Research (SOAR) telescope. One of the two 8-m telescopes comprising the Gemini Observatory is co-located with CTIO on the Association of Universities for Research in Astronomy (AURA) property in Chile, together with more than 10 other telescopes and astronomical projects.

Cerro "mountain" in Spanish; Tololo a proper name; → inter-; American, from America, → North America Nebula; → Observatory.

certain
  تاشتیگ   
tâštig (#)

Fr.: certain   

Determined, fixed; established beyond doubt or question; indisputable. → determinism.

From O.Fr. certain, from V.L. *certanus, from L. certus "sure, fixed," originally a variant p.p. of cernere "to distinguish, decide."

Tâštig, from Mid.Pers. tâštig "certain," tâšitan "to cut, cleave, create," Mod.Pers. tarâšidan, Gilaki tâštan "to shave, scrape, cut," Av. taš- "to cut, fashion, shape, form," taša- "ax, hatchet," tašan- "creator, maker," cf. Skt. taks- "to cut, chop, form by cutting, make, create," taksan "carpenter," Gk. tekhne "art, skill, craft, method," L. textere "to weave;" PIE base *tek- "to shape, make."

certainty
  تاشتیگی   
tâštigi (#)

Fr.: certitude   

The fact, quality, or state of being certain, especially on the basis of evidence. Something that is certain. → uncertainty; → uncertainty principle.

Noun from → certain.

cesium
  سزیوم   
seziom (#)

Fr.: césium   

A soft ductile chemical element of the → alkali metal group; symbol Cs. It is found in several → silicate minerals, including pollucite. The metal oxidizes in air and reacts violently with water. → Atomic number 55; → atomic weight 132.9054; → melting point 28.4°C; → boiling point 669.3°C; → specific gravity 1.873 at 20°C; and → valence +1. Cesium has several radioactive isotopes, among which 134Cs with a half-life of 2.07 years and 137Cs with a half-life of 30.3 years. Cesium was discovered spectroscopically in 1860 by W. Bunsen and G. Kirchhoff in mineral water from Durkheim.

From L. caesius "bluish gray," which was the color of the cesium line in the spectroscope, + → -ium.

cesium clock
  ساعت ِ سزیوم   
sâ'at-e seziom

Fr.: horloge à cesium   

atomic fountain clock.

cesium; → clock.

Cetus
  کتوس   
Ketus

Fr.: Baleine   

The Whale, or Sea Monster. A large, rather inconspicuous → constellation in the equatorial region of the sky at R.A. 1h 30m, Dec. -10°. Its brightest star (Diphda) is a 2nd magnitude and contains → Mira Ceti, the first-known variable star, and the → Seyfert galaxy M77. Abbreviation: Cet; genitive form: Ceti.

Named after the sea monster in Gk. mythology sent by Poseidon to punish the Queen → Cassiopeia for bragging that she or her daughter → Andromeda was more beautiful than the Nereides. But → Perseus rescued Andromeda.

Ketus, from Gk., Arabicized form Qeytas (قیطس).

CGS system
  راژمان ِ CGS   
râžmân-e CGS

Fr.: système CGS   

The system of → CGS units.

CGS unit; → system.

CGS units
  یکاهای ِ س.گ.ث   
yekâhâ-ye CGS (#)

Fr.: unités CGS   

A → metric system of physical units based on → centimeter (length), → gram (mass), and → second (time).

CGS, the initials of → centimeter, → gram, and → second; meter, kilogram, and second; → unit.

<< < -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 > >>