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: 383
overload
  بیش‌بار   
biš-bâr

Fr.: surcharge   

Electricity: Any load which exceeds the rated output of a machine, transformer, or other apparatus.

over-; → load.

oversampling
  بیش‌نمونان‌گیری   
biš-nemunângiri

Fr.: suréchantillonnage   

The process of sampling a signal with a frequency higher than the → Nyquist frequency. The signal is said to be oversampled β times, where the oversampling ratio is defined as β = (sampling frequency)/(Nyquist frequency).

over-; → sampling.

overshooting
  فرازد   
farâzad

Fr.: dépassement   

A situation in stellar interiors when the momentum of a particle carries it past its equilibrium point.

over-; shooting, from shoot, from O.E. sceotan "to shoot" (cf. O.N. skjota, Du. schieten, Ger. schießen), from PIE base *skeud- "to shoot, to chase, to throw, to project."

Farâzad, from farâ- "over, over against; foremost; before; onward" (Mid.Pers. fra-; O.Pers. fra- "forward, forth;" Av. frā "forth," pouruua- "first"; cf. Skt. pūrva- "first," pra- "before, formerly;" Gk. pro; L. pro; O.E. fyrst "foremost," superlative of fore, E. fore) + zad past stem of zadan "to strike, beat, dash against; to shoot" ( Mid.Pers. zatan, žatan; O.Pers.; Av. jan-, gan- "to strike, hit, smite, kill" (jantar- "smiter"); cf. Skt. han- "to strike, beat" (hantar- "smiter, killer"); Gk. theinein "to strike," phonos "murder;" L. fendere "to strike, push;" Gmc. *gundjo "war, battle;" PIE *gwhen- "to strike, kill").

overtake
  فرازرسیدن   
farâzrasidan

Fr.: rattraper   

To catch up with in traveling or pursuit; draw even with (Dictionary.com).

over-; → take.

Farâzrasidan, from farâz "upon, above, over," → height, + rasidan "to attain, to arrive," → access.

overtone
  اَبَرتن   
abarton (#)

Fr.: harmonique   

A note of lesser intensity and higher frequency than the fundamental note, and superimposed upon the latter to give a note of characteristic quality. Overtones whose frequencies are an integral multiple of the fundamental are said to form a harmonic series. The fundamental with a frequency f1 is the first harmonic. The frequency 2f1 is the first overtone and so on.

over-; → tone.

overvoltage
  بیش‌ولتاژ   
biš-voltâž

Fr.: surtension   

Voltage which exceeds the normal value between a conductor and earth.

over-; → voltage.

Owl Nebula
  میغِ بوف، ~ِ جغد   
miq-e buf, ~ joqd

Fr.: Nébuleuse de la Chouette   

A planetary nebula in the constellation → Ursa Major, one of the four planetary nebulae in → Messier catalog. It is one of the more complex planetary nebulae known. Its appearance has been interpreted as that of a cylindrical torus shell viewed obliquely, so that the projected matter-poor ends of the cylinder correspond with the Owl's eyes. Also known as M97 or NGC 3587.

Discovered by Pierre Méchain in 1781, the name goes back to Lord Rosse, who first used it in 1848. Owl, from O.E. ule, from P.Gmc. *uwwalon (cf. Du. uil, O.H.G. uwila, Ger. Eule), a diminutive of root *uwwa, which is imitative of an owl's hoot (cf. L. ulula "owl;" Gk. ololyzein "to cry aloud," Skt. uluka- "owl.;" → nebula.

Miq, → nebula; buf "owl;" Mid.Pers. bûf "owl," Av. buxti- "hiss, howling;" cf. Skt. bukk- "to bark, yelp;" Gk. buas "owl;" L. bubo "owl" (Fr. hibou); Arm. bou "owl." Joqd "owl," probably related to jiq "shreak, clamour, cry."

oxidant
  ا ُکسنده   
oksandé (#)

Fr.: oxydant   

The substance which supplies the → oxygen in an → oxidation → reaction. Same as → oxydizing agent agent and → oxidizer.

Agent noun from → oxidize.

oxidation
  ا ُکسایش   
oksâyeš (#)

Fr.: oxydation   

The combination of → oxygen with a substance, or the removal of → hydrogen from it.

Verbal noun of → oxidize.

oxidation number
  شمار ِ اکسایش   
šomâr-e oksâyeš

Fr.: nombre d'oxydation   

The total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom. In other words, the charge that atom would have if the compound was composed of ions. The oxidation number of an atom is zero in a neutral substance that contains atoms of only one element. Same as → oxidation state.

oxidation; → number.

oxidation state
  استات ِ اکسایش   
estât-e oksâyeš

Fr.: état d'oxydation   

Same as → oxidation number.

oxidation; → state.

oxide
  ا ُکسید   
oksid (#)

Fr.: oxyde   

A compound of → oxygen and another → chemical element.

From Fr. oxyde, from oxygène, → oxygen and acide, → acid.

oxidizable
  ا ُکسیدنی   
oksidani (#)

Fr.: oxydable   

Capable of undergoing a → chemicalreaction with → oxygen.

oxidize + → -able.

oxidize
  ا ُکسیدن   
oksidan (#)

Fr.: oxyder   

To convert a → chemical element into an → oxide; combine with → oxygen.

oxide + → -ize.

oxidized
  ا ُکسیده   
oksidé (#)

Fr.: oxydé   

Combined with or having undergone a chemical → reaction with → oxygen.

Past participle of → oxidize.

oxidizer
  ا ُکسنده   
oksandé (#)

Fr.: oxydant   

A substance that → oxidizes another substance. Same as → oxidant and → oxidizing agent.

Agent noun from → oxidize.

oxidizing agent
  کنشگر ِ اکسنده   
konešgar-e oksandé

Fr.: oxydant   

A substance that brings about an → oxidation. Same as → oxidant and → oxidizer.

oxide; → -ize; → -ing; → agent.

oxygen
  اکسیژن   
oksižen (#)

Fr.: oxygène   

A gaseous → chemical element; symbol O. Oxygen is the most abundant element in the → Universe not produced in the → Big Bang, and the third most common overall. It is a colorless, tasteless, odorless gas that is the second most abundant constituent of dry air (20.95% by volume). → Atomic number 8; → atomic weight 15.9994; → melting point -218.4°C; → boiling point -182.962°C; → density 1.429 grams per liter at STP.

Fr. oxygène, coined in 1777 by the Fr. chemist Antoine-Laurent Lavoisier (1743-1794), from Gk. oxys "sharp, acid" + Fr. -gène "something that produces" from Gk. -genes "formation, creation" (cognate with Pers. zâdan "to bring forth, give birth;" Mid.Pers. zâtan; Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born;" cf. Skt. janati "begets, bears;" L. gignere "to beget," nasci "to be born," as above, PIE base *gen- "to give birth, beget").

Oksižen, loan from Fr., as above.

oxygen burning
  سوزشِ اکسیژن   
suzeš-e oksižen

Fr.: combustion de l'oxygène   

The stage when a star fuses → oxygen into → silicon and → sulfur. It occurs only in → massive stars, with a mass over eight → solar masses.

oxygen; → burning.

ozone
  ازون   
ozon (#)

Fr.: ozone   

A form of oxygen, O3, in which the molecule is made of three atoms instead of the usual two.

From Ger. Ozon, coined in 1840 by Ger. chemist Christian Friedrich Schönbein (1799-1868) from Gk. ozon, neute pr.p. of ozein "to smell." So called for its peculiar odor.

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