An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 570
cambarvâr (#)

Fr.: toroïde   

A surface of revolution obtained by rotating a closed plane curve about an axis parallel to the plane which does not intersect the curve. The simplest toroid is the → torus. The solid enclosed by such a surface.

From tor-, from → torus + → -oid.

toroidal magnetic field
  میدان ِ مغناتیسی ِ چنبروار   
meydân-e meqnâtisi-ye cambarvâr

Fr.: champ magnétique toroïdal   

A magnetic field which is generated in a → plasma inside a → toroid, as in a → tokamak, by the electric current which spirals around the toroid. Toroidal field has no radial component. → poloidal magnetic field.

toroid; → magnetic field.

gaštâvar (#)

Fr.: couple   

The tendency of a → force applied to an object to cause the object to → rotate about a given → axis or → point. Torque is the rotational analogue of or the turning effect of a force. It is equal to the product of the force and its distance from the reference axis. More specifically, if a force F acts on a single particle at a point P whose position with respect to the origin O of the inertial reference is given by the distance vector r, the torque T acting on the particle with respect to the origin O is defined as: T = r × F. Torque is a → vector quantity. Its magnitude is given by: rF sin θ, where θ is the angle between r and F; its direction is normal to the plane formed by r and F. The sense is given by the → right-hand screw rule for the → vector product of two vectors. Torque has the same dimensions as work, but work is a scalar.

From L. torquere "to twist;" cf. Skt. tarku- "spindle;" maybe Mod.Pers. duk "spindle;" Mid.Pers. dôk "spindle;" O.C.S. traku "band, girdle," O.H.G. drahsil "turner," Ger. drechseln "to turn on a lathe;" O.E. thweorh "transverse, perverse, angry, cross;" E. thwart; PIE base *twork-/*twerk- "twist"

Gaštâvar literally "that which makes turn, turning agent," from gašt "turning," past stem of gaštan, gardidan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend") + âvar agent noun of âvardan "to bring; to cause, produce" (Mid.Pers. âwurtan, âvaritan; Av. ābar- "to bring; to possess," from prefix ā- + Av./O.Pers. bar- "to bear, carry," bareθre "to bear (infinitive)," bareθri "a female that bears (children), a mother;" Mod.Pers. bordan "to carry;" Skt. bharati "he carries;" Gk. pherein; L. fero "to carry").

torr (#)

Fr.: torr   

A unit of pressure used in the field of high vacuum, equivalent to 1 mm of mercury

After the Italian scientist Evangelista Torricelli (1608-1647), who invented the first barometer.

lâhez (#)

Fr.: torrent   

A stream of water flowing with great rapidity and violence. See also → rapids.

M.E., from M.Fr. torrent, from L. torrentem (nominative torrens) "a rushing (stream)," from torrere, "to parch, dry up, roast," → torrid.

Lâhez, from Tabari lahez "an overwhelming flow," Baxtiyâri lâhiz "flood." The first component lâh, lah maybe related to lur, Lori, Kordi laf, Tabari "flood," → cataclysm.

Torricelli's law
  قانون ِ توریچلی   
qânun-e Torricelli

Fr.: loi de Torricelli   

In fluid dynamics, a theorem that relates the speed of fluid flowing out of an opening to the height of fluid above the opening: v = (2gh)1/2, where v is the exit velocity of the water, h is the height of the water column, and g is the acceleration due to gravity (9.81 m/s2). It was later shown to be a particular case of → Bernoulli's theorem.

After the Italian scientist Evangelista Torricelli (1608-1647), who found this relationship in 1643.

  تفسان، تفسا   
tafsân, tafsâ

Fr.: torride   

Subject to the weather that is hot and dry enough to scorch land.

From L. torridus "dried with heat, scorching hot," from torrere "to dry up, roast," related to terra "earth," literally "dry land;" from PIE base *ters- "to dry" (cf. Pers. tešné "thirsty;" Mid.Pers. tašnak "thirsty;" Av. taršu- "dry," taršna- "thirst;" Skt. trsta- "dry," tars- "to be thirsty;" Gk. teresesthai "to become or be dry;" Goth. þaursus "dry, barren," O.H.G. derren "to make dry," durst "thirst;" Ger. dürr "arid;" O.E. þurstig "thirsty").

Tafsân, tafsâ, from tafsidan "to become hot," variants tâftan, tâbidan "to shine;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "; to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."

Torrid Zone
  زنار ِ تفسان   
zonnâr-e tafsân

Fr.: Zone torride   

The part of the Earth's surface between the tropics of Cancer and Capricorn

torrid; → zone.

cambar (#)

Fr.: tore   

A surface produced by the revolution of a conic section (such as a circle) around a line lying in its plane, but not cutting the conic. The solid enclosed by such a surface.

From L. torus "a round, swelling protuberance."

Cambar "torus," originally "hoop, circle," from Mid.Pers. cambar "hoop; a ring-shaped headdress," cambar vâcik "playing tambourine."


Fr.: total   

Constituting or comprising the whole; entire; complete in extent or degree. Related term → general = harvin (هروین).

M.E., from O.Fr. total, from M.L. totalis "entire, total," from L. totus "all, whole, entire," of unknown origin.

Mid.Pers. hamâk, hamâg "total, all," hamâkih "totality," related to Mod.Pers. hamé- "all," variant hami "all the time, always;" Mid.Pers. hamê "all the time, always;" Av. hama- "any" (cf. Skt. sama-"any, every, whichever;" Gk. amo-then "whichever;" Goth. sums "any;" O.N. sumr "any;" O.E. sum "some;" E. some) + suffix -âk.

total abundance
  فراوانی ِ هماک   
farâvâni-ye hamâk

Fr.: abondance totale   

Same as → elemental abundance.

total; → abundance.

total eclipse
  گرفت ِ هماک   
gereft-e hamâk

Fr.: éclipse totale   

An → eclipse in which the whole of the disk of the Sun or Moon is obscured. See also → annular eclipse, → partial eclipse, → totality, → totality path.

total; → eclipse.

total energy
  کاروژ ِ هماک   
kâruž-e hamâk

Fr.: énergie totale   

The sum of all forms of energy involved in a system.

total; → energy.

total function
  کریای ِ هماک   
karyâ-ye hamâk

Fr.: fonction totale   

A function whose value is defined for all possible input values.

total; → function.

total gravity
  گرانی ِ هماک   
gerâni-ye hamâk

Fr.: gravité totale   

In a → rotating star, the sum of the → gravitational, → centrifugal, and → radiative accelerations. See also → effective gravity.

total; → gravity.

total internal reflection
  بازتاب ِ هماک ِ درونی   
bâztâb-e hamâk-e daruni

Fr.: réflexion totale interne   

A phenomenon occurring when a light ray traveling cross an → interface from a higher → refractive index medium to a lower refractive index medium hits the interface at an angle larger than the → critical angle. In these conditions the light will not pass through to the second → medium at all. Instead, all of it will be reflected back into the first medium.

total; → internal; → reflection.

total lunar eclipse
  ماه‌گرفت ِ هماک   
mâhgereft-e hamâk

Fr.: éclipse lunaire totale   

A → lunar eclipse when the entire → Moon passes through the Earth's → umbra. The maximum duration of a total lunar eclipse is 1h 47m. It happens when the Moon crosses the umbra at its → apogee, where it moves the most slowly, and the Earth is at its → aphelion. The longest total lunar eclipse of the 21st century, lasting 1h 42m 59s, occurred on the night of 27 to 28 July 2018 (Europe, Africa, Asia, Australia, and New Zealand). See also → tetrad.

total; → lunar; → eclipse.

total pressure
  فشار ِ هماک   
fešâr-e hamâk

Fr.: pression totale   

The sum of → static pressure, → dynamic pressure, and → hydrostatic pressure in the → Bernoulli equation.

total, → pressure.


Fr.: totalitaire   

1) Of or relating to a centralized government that does not tolerate parties of differing opinion and that exercises dictatorial control over many aspects of life.
2) Exercising control over the freedom, will, or thought of others; authoritarian; autocratic.
3) An adherent of totalitarianism (

From totali-, from → totality + -arian, a suffix forming adjectives or nouns ending in → -ary.

Hamâkigerâyi, from hamâki, → totality, + -gerâ, → ist.


Fr.: totalitarisme   

1) The practices and principles of a totalitarian regime.
2) Absolute control by the state or a governing branch of a highly centralized institution (

totalitarian; → -ism.

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