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: 551
thermohaline mixing
  آمیزش ِ گرماشور   
âmizeš-e garmâšur

Fr.: mélange thermohaline   

In stars, an instability phenomenon, reminiscent of the → thermohaline convection in the oceans, that takes place when layers of higher molecular weight occur above a region of lower molecular weight. A situation of heavier material being above lighter gas in a star can occur during the → helium flash when → helium burning does not start in the center but in the shell. Similarly, in → close binary systems it may happen that helium-rich material is transferred to a → main sequence star. Then a helium-rich outer layer is formed and the instability occurs at the interface between that layer and the original stellar material. This process can explain several surface abundance variations in stars. First discussed by S. Kato (1966, Publ. Astron. Soc. Japan 18, 374).

thermohaline; → mixing.

thermonuclear flash
  درخش ِ گرماهسته‌ای   
deraxš-e garmâhaste-y

Fr.: flash thermonucléaire   

A theoretical interpretation for the → X-ray bursts observed toward → low-mass X-ray binary (LMXB) stars. According to models, X-ray bursts are produced on the surface of → neutron stars as a result of violent thermonuclear processes in a → hydrogen or → helium rich → layer. It is the → nuclear energy released in the → fusion of hydrogen and helium to heavier elements (e.g., Ni, Zn, and Se) in the → accreted matter which heats the upper layers of the neutron star so that X-rays are emitted from the surface (see, e.g., Taam, R.E., 1984, AIP Conf. Proc. 115, 263).

thermonuclear; → flash.

thermonuclear reaction
  واژیرش ِ گرماهسته‌ای   
vâžireš-e garmâhaste-yi (#)

Fr.: réaction thermonucléaire   

A nuclear reaction in which two or more atomic nuclei fuse into a single heavier nucleus by a collision of the interacting particles at extremely high temperatures. Chains of thermonuclear reactions, such as the → proton-proton chain and the → CNO cycle, account for the energy radiated from the Sun and more massive stars.

thermo- + → nuclear; → reaction.

thermonuclear runaway
  واژیرش ِ گرماهسته‌ای ِ لگام گسیخته   
vâžireš-e garmâhaste-yi-e legâm gosixté

Fr.: emballement thermonucléaire   

1) The uncontrolled → fusion of hydrogen into helium.
2) A → thermonuclear reaction process occurring at electron → degenerate conditions in stellar material, such as in → Type Ia supernovae.

thermonuclear; → runaway.

Vâžireš, → reaction; garmâhaste-yi, → thermonuclear; legâm gosixté literally "rampant, unrestrained," from legâm "bridle, rein" + gosixté "broken off, torn away," p.p. of gosixtan "to tear away, to break off."

thermonuclear supernova
  ابر-نو-اختر ِ گرماتوانیک   
abar-now-axtar-e garmâtavânik

Fr.: supernova thermonucléaire   

Same as → type Ia supernova

thermonuclear; → supernova.

thermosphere
  گرماسپهر   
garmâsepehr

Fr.: thermosphère   

The region of the upper atmosphere in which temperature increases continuously with height, starting at roughly 100 km. The thermosphere includes the exosphere and most of the ionosphere.

thermo-; → sphere.

thermostat
  دماپای   
damâpây (#)

Fr.: thermostat   

A device for maintaining a system at constant temperature by automatically terminating or restoring the heating or cooling source. It consists of a temperature sensing instrument connected to a switching device. The sensing device is often a bimetallic strip which triggers a simple electric switch.

thermo- + → -stat.

thesaurus
  واژگنج   
vâžganj

Fr.: thésaurus   

1) A controlled and structured list of terms or descriptors usually with a cross-reference system used in subject analysis and information retrieval in a particular field.
2) More generally, a work that lists words arranged and grouped according to their semantic similarities, including synonyms and sometimes antonyms. This is different from the dictionary, which contains definitions and pronunciations. The first major work of this kind in English is Peter Mark Roget's Thesaurus of English words and phrases, Classified and Arranged so as to Facilitate the Expression of Ideas (1852).

From L. thesaurus "treasury, treasure," from Gk.  thesauros  "treasure, treasury, storehouse," from root of  tithenai "to put, to place," → thesis.

Vâžganj, from vâž, → word, + ganj "treasure," from Mid.Pers. ganj "treasure."

thesis
  ۱) دایش؛ ۲) دایش‌نامه، پایان‌نامه   
1) dâyeš; 2) dâyeš-nâmé, pâyân-nâmé

Fr.: thèse   

1) A proposition put forward for consideration, especially one to be discussed and proved or to be maintained against objections.
Philo.: The first of three stages in Hegelian dialectic; the inevitable transition of thought, by contradiction and reconciliation, from an initial conviction to its opposite and then to a new, higher conception that involves but transcends both of them. → antithesis; → synthesis.
2) A dissertation based on original research, especially as work toward an academic degree.

M.E., from L., from Gk. thesis "a proposition; a setting down, something set down," from root of tithenai "to place, put, set," cognate with Pers. dâdan "to give," as below.

1) Dâyeš "giving, setting down," from O.Pers./Av. dā- "to give, grant, put," dadāiti "he gives;" Mid.Pers./Mod.Pers. dâdan "to give; to put" (cf. Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do") + -y- epenthetic vowel + -eš verbal noun suffix.
2) Dâyeš-nâmé, from dâyeš "thesis" + nâmé "diploma, letter" (Mid.Pers. nâmag "book, letter, inscription," from O.Pers./Av. nāman- "name;" cf. Skt. nama-; Gk. onoma, onuma; L. nomen; PIE *nomen-).
Pâyân-nâmé, literally "ending, final diploma," from pâyân "end," → terminal + nâmé.

thick
  ستبر   
setabr (#)

Fr.: épais   

Relatively great in extent from one surface to the opposite; deep or profound. &rarroptically thick

M.E. thikke, O.E. thicce "not thin, dense," from P.Gmc. *theku-, *thekwia- (cf. O.S. thikki, O.H.G. dicchi, Ger. dick), from PIE *tegu- "thick."

Setabr, from Mid.Pers. stabr "strong, big," stambag "pugnacious, opposing;" O.Pers. (mā) stabava [2sg.inj.] "to revolt;" Av. stabra- "strong, firm;" cf. Skt. stabh- "support," stambh- "to support, fix firmly," stabhnāti "supports;" Gk. astemphes "steadfast," stephein "to tie around, encircle," astemphes "firm, rigid;" Lith. stebas "staff, pillar," stembti "to oppose."

thick disk
  گرده‌ی ِ ستبر، دیسک ِ ~   
gerde-ye setabr, disk-e ~

Fr.: disque épais   

A disk component of a → spiral galaxy that lies above the → thin disk and mainly consists of stars. The thick disk of our → Galaxy makes up about 10-50% of the stellar mass of the → Milky Way and has a scale height of ~ 1,000-3,000 → light-years. Thick disk stars are, on average, moving faster in a vertical direction with respect to the → galactic plane than thin disk stars. In contrast to thin disk, the stars within the thick disk are almost all older than 10 billion years and typically have a smaller → metallicity than the average values for the thin disk stars. These facts suggest that the formation scenarios for the thin and thick disks were different. In particular, it is thought that the thick disk is much older than the thin disk.

thick; → disk;

thick lens
  عدسی ِ ستبر   
adasi-ye setabr

Fr.: lentille épaisse   

A lens whose thickness is not small compared with its focal length. The thick lens may include several components, which may or may not be in contact. → thin lens.

thick; → lens.

thickness
  ستبرا   
setabrâ (#)

Fr.: épaisseur   

The state or quality of being thick. → optical thickness.

M.E. thiknesse, O.E. thicnes, from → thick + -nes(s) suffix of action, quality or state, cf. M.Du. -nisse, O.H.G. -nissa, Ger. -nis, Goth. -inassus.

Setabrâ, from setabrthick + a suffix forming nouns from adjectives.

thin
  نازک   
nâzok (#)

Fr.: mince   

Having relatively little extent from one surface or side to the opposite; not thick. → optically thin; → superthin galaxy.

M.E. thyn(ne), O.E. thynne, from P.Gmc. *thunnuz, *thunw- (cf. W.Fris. ten, M.L.G. dunne, Du. dun, O.H.G. dunni, Ger. dünn), from PIE *tnus-, *tnwi-, from base *ten- "stretch;" cf. Pers. tonok "thin, slender," → attenuate.

Nâzok, from Mid.Pers. nâzuk, nâzik "tender, gentle."

thin disk
  گرده‌ی ِ نازک، دیسک ِ ~   
gerder-ye nâzok, disk-e ~

Fr.: disque mince   

A disk component of a → spiral galaxy containing → stars, → gas, and → dust which are confined to the galaxy's → plane of rotation. In contrast to → thick disks, thin disks contain the bulk of the → baryonic matter in spiral galaxies. For example, on the order of 60-90% of the baryonic matter in the → Milky Way is located in the thin disk. The scale height of the thin disk in the Milky Way is about 400 → light-years, whereas its scale length is about 10,000 light-years. Moreover, the outer regions of thin disks appear to be bent by the → warp phenomenon. The thin disks of spiral galaxies are active sites of → star formation, especially in the spiral arms. For this reason, stars in the thin disk tend to be relatively young. Thin disk stars also tend to be → metal-rich compared with thick disk and → halo stars, and typically have a → metallicity similar to that of the Sun.

thin; → disk;

thin lens
  عدسی ِ نازک   
adasi-ye nâzok (#)

Fr.: lentille mince   

A lens whose thickness is considered small in comparison with the distances generally associated with its optical properties. Such distances are, for example, radii of curvature of the two spherical surfaces, primary and secondary focal lengths, and object and image distances. → thick lens.

thin; → lens.

thing
  چیز   
ciz (#)

Fr.: chose   

1) A material object without life or consciousness; an inanimate object.
2) Some entity, object, or creature that is not or cannot be specifically designated or precisely described.
3) Anything that is or may become an object of thought (Dictionary.com).

M.E. thing; O.E. þing "meeting, assembly, discussion;" cf. O.Norse þing "assembly, meeting, council;" O.Frisian thing "assembly, action, matter, thing;" O.Saxon thing; O.Du. dinc "law suit, matter, thing;" M.Du. ding; Du. ding; O.Ger. ding, dinc "assembly;" M.H.G. dinc "assembly;" Ger. ding "matter, affairs, thing." Hence, the word originally meant "assembly, meeting," then came to mean a specific issue discussed at such an assembly, and finally came to indicate "an object."

Ciz, from Mid.Pers. ciš, tis "thing, affair;" O.Pers. cišciy "anything."

think
  اندیشیدن   
andišidan

Fr.: penser, réfléchir   

To employ one's mind rationally and objectively in evaluating or dealing with a given situation.

M.E. thinken, variant of thenken, O.E. thencan; P.Gmc. *thankjan (cf. O.Fris. thinka, O.S. thenkian, O.H.G. denchen, Ger. denken, Goth. thagkjan).

Andišidan, infinitive from andiš-; Mid.Pers. handeš-, handešidan "to think, consider, reflect," ultimately from Proto-Iranian *ham-dis-, from *ham- "together, with, same," → syn- + *dis- "form, appearance," cf. Av. daēs- "to show," daēsa- "sign, omen;" Mod.Pers. dis, disé "form, appearance," variants -diz, -diš; Mid.Pers. dêsag "form, appearance," dêsidan "to form, build;" Sogd. andiš "to seem," andêš "to show," andêšik "appearing;" cf. Skt. deś- "to show, point out;" PIE *deik- "to show" (cf. Gk. deiknumi "to show," dike "manner, custom;" L. dicere "to utter, say;" O.H.G. zeigon, Ger. zeigen "to show;" O.E. teon "to accuse," tæcan "to teach").

third
  سوم   
sevom (#)

Fr.: troisième   

Next after the second; the ordinal number for three. → Newton's third law of motion; → third contact; → third dredge-up; → third law of thermodynamics.

M.E. thirde, O.E. (north) thirda, variant of ridda, from P.Gmc. *thridjas (cf. O.Fris. thredda, O.S. thriddio, M.L.G. drudde, Du. derde, O.H.G. dritto, Ger. dritte, Goth. thridja).

Sevom, ordinal number for , → three.

third contact
  پرماس ِ سوم   
parmâs-e sevom

Fr.: troisième contact   

The end of the total phase of a solar eclipse marked by the trailing edge of the Moon first revealing the Sun.

third; → contact.

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