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: 179
uniformitarianism
  یکدیسوارباوری   
yekdisvârbâvari

Fr.: uniformitarisme   

The doctrine whereby geologic processes (→ erosion, → deposition, → compaction, and → uplift) observed at Earth's surface now are the same that have shaped Earth's landscape over long periods of time in the past. The term uniformitarianism was first used in 1832 by William Whewell, to present an alternative explanation for the origin of the Earth. The prevailing view at that time was that the Earth was created through supernatural means and had been affected by a series of catastrophic events such as the biblical Flood. This theory is called → catastrophism. The ideas behind uniformitarianism originated with the work of Scottish geologist James Hutton. In 1785, Hutton presented at the meetings of the Royal Society of Edinburgh that the Earth had a long history and that this history could be interpreted in terms of processes currently observed. For example, he suggested that deep soil profiles were formed by the weathering of bedrock over thousands of years. He also suggested that supernatural theories were not needed to explain the geologic history of the Earth (PhysicalGeography.net).

uniformitarian; → -ism.

uniformity
  یکدیسواری، یکدیسیگی   
yekdisvâri, yekdisigi

Fr.: uniformité   

The state or quality of being uniform.

uniform; → -ity.

unify
  یگانستن، یگانیدن   
yegânestan (#), yegânidan (#)

Fr.: unifier   

To make or become a single unit or entity. → grand unified theory

M.Fr. unifier, from L.L. unificare "to make one," from L. uni-, → one, + facere "to make" (cf. Fr. faire, Sp. hacer), from PIE base *dhe- "to put, to do" (cognate with Mod.Pers. dâdan "to give;" O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives; puts;" Skt. dadáti "puts, places;" Hitt. dai- "to place;" Gk. tithenai "to put, set, place;" Lith. deti "to put;" Czech diti, Pol. dziac', Rus. det' "to hide," delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do").

Yegânestan, yegânidan "to make one," infinitive from yek, → one.

unimaginable
  ناویناردنی   
nâvinârdani

Fr.: inimaginable   

Difficult or impossible to believe.

un-; → imaginable.

union
  یکایش   
yekâyeš

Fr.: union   

General: The act of uniting two or more things.
A number of persons, organizations, states, etc., joined or associated together for some common purpose, e.g. → International Astronomical Union (IAU).
Math.: A set containing all the elements of two or more sets being combined. It is represented by ∪.

M.E. from O.Fr. union from L.L. unionem (nominative unio) "oneness, unity," from unus, → one, cognate with Pers. yek, as below.

Yekâyeš, from yek, → one, + -ây- epenthetic vowel, + -eš verbal noun suffix, → -tion.

unique
  یکتا   
yektâ (#)

Fr.: unique   

Existing as the only one or as the sole example.
Limited to a single outcome or result. → uniqueness theorem.

From Fr. unique, from L. unicus "single, sole," from unus, → one.

Yektâ "unique," from yek, → one, + "fold, plait, ply; piece, part" (Mid.Pers. tâg "piece, part").

uniqueness
  یکتایی   
yektâyi (#)

Fr.: unicité   

The state or condition of being → unique.

Noun from → unique.

uniqueness theorem
  فربین ِ یکتایی   
farbin-e yektâyi

Fr.: théorème d'unicité   

1) Physics: A → potential that satisfies both → Poisson's equation and the → boundary conditions pertinent to a particular field is the only possible potential.
2) Math.: If two → continuous functions φ(t) and ψ(t) have one and the same → Laplace transform F(p), then these functions are identically equal.
3) Astro.: A → black hole can only be characterized by its → mass, → electric charge, and → angular momentum. See also → no hair theorem.

uniqueness; → theorem.

unit
  یکا، یکان   
yekâ (#), yekân (#)

Fr.: unité   

A quantity or dimension adopted as a standard of measurement.
Math.: The lowest positive natural number.
The first digit to the left of the decimal point in decimal notation, representing a whole number less than ten.
An element in a ring that has a multiplicative inverse.

Back formation from → unity.

Yekâ, yekân, from yek, → one.

unit vector
  بردار ِ یکا   
bordâr-e yekâ

Fr.: vecteur unité   

A vector of length 1, also called a direction vector.

unit; → vector.

unitarity
  یکاییگی   
yekâyigi

Fr.: unitarité   

1) The condition of being → unitary.
2) → quantum unitarity.

unitary; → -ity.

unitary
  یکایی   
yekâyi

Fr.: unitaire   

1) Of or pertaining to a unit or units; having the indivisible character of a unit.
2) Math.: An → operator  U satisfying the relations: U+ U = 1, U U+ = 1, where U+ is the → adjoint .

unit + -ary.

unitary group
  گروه ِ یکایی، ~ یکانی   
goruh-e yekâyi, ~ yekâni

Fr.: groupe unitaire   

The set of n × n unitary matrices (→ unitary matrix).

unitary; → group.

unitary matrix
  ماتریس ِ یکایی، ~ یکانی   
mâtris-e yekâyi, ~ yekâni

Fr.: matrice unitaire   

A square matrix whose inverse equals its adjoint.

unitary; → matrix.

unitary operator
  آپارگر ِ یکایی   
âpârgar-e yekâyi

Fr.: opérateur unitaire   

A linear operator whose inverse is its → adjoint. In addition to → Hermitian operators, unitary operators constitute a fundamentally important class of quantum-mechanical operators.

unitary; → operator.

unitary transformation
  ترادیس ِ یکایی، ~ یکانی   
tarâdis-e yekâyi, ~ yekâni

Fr.: transformation unitaire   

A transformation whose reciprocal is equal to its Hermitian conjugate.

unitary; → transformation.

unite
  آیکیدن، هم‌یکیدن   
âyekidan, ham-yekidan

Fr.: unir   

To join, combine, or incorporate so as to form a single whole or unit.

M.E. uniten, from L. unitus, p.p. of unire "to unite," from unus, → one.

Âyekidan, from â- nuance/strengthening prefix + yek, → one, + -idan infinitive suffix; ham-yekidan, from ham- "together," → syn-, + yekidan.

united
  آیکیده، هم‌یکیده   
âyekidé, ham-yekidé

Fr.: uni   

Formed by or resulting from the union of two or more persons or things.

P.p. of → unite.

unity
  یکی   
yeki (#)

Fr.: unité   

The state or condition of being one.
Math.: One.

M.E. unite, from O.Fr., from L. unitatem "oneness, sameness, agreement," from unus, → one.

Yeki, noun from yek, → one.

univariate
  یکورتا   
yekvartâ

Fr.: univarié   

Statistics: Involving only one variable.

uni-; → variate.

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