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: 3079 Search : on
observational effect
  ا ُسکر ِ نپاهشی   
oskar-e nepâheši

Fr.: effet observationnel   

A feature appearing in an observation, which is not intrinsic to the object observed, but is due to the inappropriate method used (e.g. limited angular resolution).

observational; → effect.

observational error
  ایرنگ ِ نپاهشی   
irang-e nepâheši

Fr.: erreur observationnelle   

The difference between a measured value of quantity and its true value.

observational; → error.

occasion
  آکتن   
âkatan

Fr.: occasion   

1) A particular time, especially as marked by certain circumstances or occurrences.
2) A special or important time, event, ceremony, celebration, etc.
3) A convenient or favorable time, → opportunity, or juncture (Dictionary.com).

M.E. occasioun from O.Fr. ochaison, ocasion "cause, reason, pretext; opportunity," from L. occasionem (nominative occasio) "appropriate time," from occasum, occasus "fall; sunset," p.p. of occidere "fall down, go down," from ob "down, away" + cadere "to fall," → case.

Âkatan, from prefix â- + katan "to fall," cf. Laki: katen "to fall," kat "he/she fell," beko! "fall!" (an insult); katyâ "fallen;" Lori: kat "event, error;" Kurd. (Soriani): kawtin "to fall, befall," kett "fallen;" Kurd. (Kurmanji): da.ketin "to fall down;" Lârestâni: kata "to fall;" Garkuyeyi: darkat, varkat "he/she fell (sudden death);" Gilaki (Langarud, Tâleš): katan "to fall," bakatam "I fell," dakatan "to fall (in a marsh, in a pit)," vakatan "to fall from tiredness, be exhausted," fakatan "to fall from (i.e., lose) reputation;" Tabari: dakətə "fallen," dakətən "to crash down," dakət.gu "stray cow;" Proto-Iranian *kat- "to fall;" cf. L. cadere "to fall," → case, Pers. kâté.

occasional
  آکتنی   
âkatani

Fr.: occasionnel   

1) Occurring or appearing at irregular or infrequent intervals; occurring now and then.
2) Intended for supplementary use when needed.
3) Pertaining to, arising out of, or intended for the occasion (Dictionary.com).

occasion; → -al.

occlusion
  برکلانش   
barkolâneš

Fr.: occlusion   

1) The process of occluding. Something that occludes.
2) Phonetics: Closure at some point in the vocal tract that blocks the flow of air in the production of an oral or nasal stop (TheFreeDictionary.com). 3) Chem.: An absorption process by which a substance adheres strongly to another.

occlude; → -tion.

occlusive consonant
  هم‌آوای ِ برکلانی   
hamâvâ-ye barkolâni

Fr.: occlusive   

A → phoneme that is produced following the obstruction of air flow in the → pharynx. The sound arises during the exhalation when the air passage is no longer blocked. English occlusive consonants are [p],[b],[t],[d],[k], and [g]. Same as → stop consonant.

occlude; → -ive.

occultation
  فروپوشانش   
forupušâneš

Fr.: occultation   

The blocking of light from an astronomical object, such as a star, by another object, such as the Moon or an asteroid, that passes in front of it. Also, the period of time for which this blocking takes place. A → solar eclipse is a particular case of occultation. Determining the moment of stellar occultation by the Moon is used to improve our knowledge of the lunar orbit. Moreover, the occultation of stars by asteroids or planetary satellites provide important data for better measuring the sizes of the occulting bodies. See also → grazing occultation.

M.E. from L. occultation- "a hiding," from occultat(us), p.p. of occultare "to conceal, keep something hidden," frequentative of occulere "to cover over, conceal," from ob "over" + a verb related to celare "to hide," from PIE base *kel- "to conceal."

Forupušân, from foru- "down, downward; below; beneath" (Mid.Pers. frôt "down, downward;" O.Pers. fravata "forward, downward;" cf. Skt. pravát- "a sloping path, the slope of a mountain") + pušân p.pr. of pušândan, accusative of pôšidan, pôš- "to cover; to wear" (related to pust "skin, hide;" Mid.Pers. pôst; O.Pers. pavastā- "thin clay envelope used to protect unbaked clay tablets;" Skt. pavásta- "cover," Proto-Indo-Iranian *pauastā- "cloth").

occupation
  هَگش   
hageš

Fr.: occupation   

The act of occupying; the state of being occupied.

Verbal noun of → occupy.

octagon
  هشت‌بر، هشت‌گوش   
haštbar, haštguš (#)

Fr.: octogone   

A polygon having eight angles and eight sides.

From L. octagonos, from Gk. oktagononos "eight-angled," from okta-, → octa-, oct- "eight," + gonia "angle," related to gony "knee," L. genu "knee," cuneus "a wedge;" Av. žnu- "knee;" Mod.Pers. zânu "knee," Skt. janu- "knee," kona- "angle, corner;" PIE base *g(e)neu-, see below.

Haštbar "eight-sided," from hašt "eight," → octa-, oct- + bar "side; breadth; breast" (Mid.Pers. var "breast;" Av. vouru "wide, broad, extended" (vourucašāni- "looking far"), related to varah- "breast;" cf. Skt. urú- "wide, broad," úras- "breast;" Gk. eurus "wide, broad;" PIE base uer-, ueru-s"wide, broad"); haštguš, from hašt, → octa-, oct-, + guš "corner, angle," Mid.Pers. gošak "corner."

octahedron
  هشتدیمه   
haštdimé

Fr.: octaèdre   

A geometric solid with eight sides.

octa-, oct-; → -hedron.

off-source observation
  نپاهش ِ اپ-خن   
nepâheš-e ap-xan

Fr.: observation hors source   

An observation when the telescope is pointed away from the source in order to measure the sky background contribution.

off-; → source; → observation.

Ohmic dissipation
  افتالِ اُهمی   
eftâl-e ohmi

Fr.: dissipation ohmique   

1) A loss of electric energy due to conversion into heat when a current flows through a resistance. Same as Ohmic loss.
2) In plasma physics, the energy released by charged particles as they make collisions with other particles.

Ohmic; → dissipation.

old stellar population
  پرینش ِ ستاره‌ای ِ کهن   
porineš-e setâre-yi-ye kohan

Fr.: population stellaire vielle   

A population of stars in a stellar system that have definitely left the → main sequence.

old; → stellar; → population.

Olympus Mons
  کوهِ اُلومپوس   
kuh-e Olumpos

Fr.: Olympus Mons   

The highest peak on Mars, and the largest volcano in the solar system. It rises to a height of 27 kilometres above the datum level selected on the basis of atmospheric pressure.This gigantic shield volcano, 700 kilometres across, is similar in nature to volcanoes on Earth but its volume is at least fifty times greater than its nearest terrestrial equivalent.

From L. Mons, → mountain, + Olympus, from Gk. Olympos a mountain (2966 m) in north-east Greece, on the boundary between Thessaly and Macedonia, mythical abode of the greater Grecian gods.

Omicron Ceti
  ا ُمیکرون کتوس   
Omikron Ketus

Fr.: Omicron Ceti   

Another name for → Mira.

Omicron, Gk. alphabet letter; Ceti, → Cetus.

Omicron Lupi
  امیکرون-گرگ   
Omikron-Gorg

Fr.: Omicron (ο) Lupi   

A bright star of → apparent visual magnitude  V = 4.3 lying in the constellation → Lupus. Among its other designations: HD 130807, HR 5528, HIP 72683. It is an → early-type star of → spectral type B5 IV and a member of the → Scorpius-Centaurus association. Ο Lupi is in fact a → binary system whose components have an angular separation of 0.043 arcsec, corresponding to a physical separation of 5.3 → astronomical units, with a mass ratio of 0.91.

Bayer designation; Lupi, genitive of → Lupus.

on-
  بر-   
bar- (#), dar- (#)

Fr.: sur   

Adverb, used as prefix denoting "in, into, onto; toward; with continuous activity," etc.

O.E. on, variant of an "in, on, into," from P.Gmc. (cf. Du. aan, Ger. an, Goth. ana "on, upon"), from PIE base *ano "on" (cf. Av. ana "on," Gk. ana "on, upon," L. an-, O.C.S. na, Lith. nuo "down from").

Bar "on; up; upon; in; into; at; forth; with; near; before; according to" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over").
Dar- "in," from Mid.Pers. andar, → intra-.

on-line
  بر-خط   
bar-xatt

Fr.: en ligne   

The state when two or more devices are directly connected and are communicating efficiently.
Of computers, operating under the direct control of, or connected to, a main computer.

on; → line.

on-line reduction
  باز‌هازشِ بر-خط   
bâzhâzeš-e bar-xatt

Fr.: réduction enligne   

Preliminary reduction of observational data at a telescope simultaneously with their acquisition.

on-line; → reduction.

on-source observation
  نپاهشِ بر-خن   
nepâheš-e bar-xan

Fr.: observation sur la source   

In comparison with → off-source observation, an observation which is concerned with the source itself.

on-; → dource; → observation.

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