An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

<< < -is bal cha dis epi gra lin non pis rel spe the > >>

Number of Results: 232 Search : ist
piston
  پیستون   
piston (#)

Fr.: piston   

A disk or cylindrical part tightly fitting and moving within a cylinder, either to compress or move a fluid collected in the cylinder, as air or water, or to transform energy imparted by a fluid entering or expanding inside the cylinder, as compressed air, explosive gases, or steam, into a rectilinear motion usually transformed into rotary motion by means of a connecting rod (Dictionary.com).

From Fr. piston, from M.Fr. piston "large pestle," from O.It. pistone "a piston," from pestare "to pound," from L.L. pistare, from pistare "to pound."

Planck distribution
  واباژش ِ پلانک   
vâbâžeš-e Planck

Fr.: distribution de Planck   

The distribution of radiation with wavelength for a blackbody, given by → Planck's radiation law.

Planck; → distribution.

Pleistocene
  پلیءستوسن   
Pleistosen

Fr.: Pléistocène   

The earliest Epoch of the Quaternary Period, beginning about 1.6 million years ago and ending 10,000 years ago. Commonly known as the "Ice Age," a time with episodes of widespread continental glaciation.

From Gk. pleisto(s), superlative of Polys "much," cognate with Pers. por, → full, + -cene from Gk. kainos "new, recent."

Poisson distribution
  واباژش ِ پو‌آسون   
vâbâžeš-e Poisson

Fr.: distribution de Poisson   

A → probability function that characterizes → discrete  → random events occurring independently of one another within some definite time or space. It may be regarded as an approximation of the → binomial distribution when the number of events becomes large and the probability of success becomes small. The Poisson distribution is expressed by: f(x) = (λxe)/x!, where λ is the mean number of successes in the interval, e is the base of the → natural logarithm, and x is the number of successes we are interested in.

Named after Siméon Denis Poisson (1781-1840), French mathematician, who developed the application of Fourier series to physical problems and made major contributions to the theory of probability and to the calculus of variations; → distribution.

polar distance
  دورای ِ قطبی   
durâ-ye qotbi

Fr.: distance polaire   

The angular distance of an object from a celestial pole. It is equal to 90° minus the object's declination.

polar; → distance.

political scientist
  کاراهیکدان   
kârâhikdân

Fr.: spécialiste en sciences politiques   

A person who studies the structure and theory of government and seeks practical and theoretical solutions to political problems.

political; → scientist.

Kârâhikdân, literally "politics scientist," from kârâhik, → politics, + dân "knower," present stem of dânestan, → science.

power-law distribution
  واباژش با قانون ِ توانی   
vâbâžeš bâ qânun-e tavâni

Fr.: distribution en loi de puissance   

For a → random variable X, any → distribution which has the form: P(X ≥ x) = (k/x)α, where x is a value in the range defined for X, k > 0 is a parameter termed location parameter, and α > 0 is the → slope parameter.

power; → law; → distribution.

principle of relativistic causality
  پروز ِ بنارمندی ِ باز‌آنیگی‌مند   
parvaz-e bonârmandi-ye bâzânigi-mand

Fr.: principe de la causalité relativiste   

One consequence of the theory of → special relativity, according to which no two events separated by a distance greater than their separation in time multiplied by the → speed of light may have a → causal influence on each other. Violation of this principle leads to → paradoxes, such as that of an → effect preceding its → cause.

principle; → relativistic; → causality.

probability distribution
  واباژش ِ شوانایی   
vâbâžeš-e šavânâyi

Fr.: distribution de probabilité   

The function that describes the range of possible values that a random variable can attain and the probability that the value of the random variable is within any (measurable) subset of that range.

probability; → distribution.

proper distance
  اپست ِ سره   
apest-e saré

Fr.: distance propre   

A distance between two nearby events in the frame in which they occur at the same time. It is the distance measured by a ruler at the time of observation. Hence, for a cosmological time t, Dproper = DC . a(t), where DC is the → comoving distance, and a(t) is the → scale factor. In the present epoch a = a(tobs) = 1, and Dproper = DC.

proper; → distance.

proper motion distance
  دورای ِ جنبش ِ سره   
durâ-ye jonbeš-e saré

Fr.: distance mouvement propre   

The distance derived from the → proper motion of an object. If an object has a known → transverse velocity  u, and has an observed angular motion of dθ/dt, then the proper motion distance is defined as: d = u/(dθ/dt).

proper; → motion; → distance

realist
  ۱) هسیاگرا، هسیاباور؛ ۲) هسیامند   
1) hasyâgerâ, hasyâbâvar; 2) hasyâmand

Fr.: réaliste   

1) A person who tends to view or represent things as they really are; an adherent of → realism.
2) Of or pertaining to realism or to a person who embodies its principles or practices.

real; → -ist.

realistic
  هسیامند   
hasyâmand

Fr.: réaliste   

1) Interested in, concerned with, or based on what is real or practical.
2) Philo.: Of or pertaining to realists or → realism.

From → real + -istic, from L. -isticus, Gk. -istikos, from -ikos, → -ic.

redshift space distortion
  چولگی ِ فضای ِ سرخ-کیب   
cowlegi-ye fazâ-ye sorx-kib

Fr.: distorsion dûe aux vitesses particulières sur la ligne de visée   

The distortion observed in → redshift space of → galaxy clusters caused by peculiar velocities of the members (→ peculiar velocity). In a perfectly homogeneous → Friedmann-Lemaitre Universe the redshifts would accurately measure radial distances from the observer, and the mapping from real space to redshift space would simply be an identity. In an inhomogeneous Universe the peculiar velocities associated with any inhomogeneous structure will introduce a distortion in this mapping (N. Kaiser, 1987, MNRAS 227, 1). See also: → fingers of God, → Kaiser effect.

redshift; → space; → distortion;.

redshift-distance relation
  بازانش ِ سرخ‌کیب-دورا   
bâzâneš-e sorxkib-durâ

Fr.: relation décalage vers le rouge-distance   

The correlation, first established by E. Hubble, between the cosmological recession velocities of galaxies and their distances.

redshift; → distance; → relation.

register
  ۱) برنوس؛ ۲) برنوسیدن   
1) barnus; 2) barnusidan

Fr.: 1) registre; 2) enregistrer   

1a) A book in which records of acts, events, names, etc., are kept; a list or → record of such acts, events, etc.
1b) An entry in such a book, record, or list.
1c) → Registration or → registry (Dictionary.com).
1d) In computer science, → registry.
2a) To enter or cause to be entered formally in a register.
2b) To enroll (a student, voter, etc.) in a school or course of study, on the voting rolls, etc. (Dictionary.com).

M.E. registre, from M.Fr., from O.Fr. registre and directly from M.L. registrum, alteration of L.L. regesta "list, matters recorded," noun use of L. regesta, from regestus, p.p. of regerere "to record; retort," literally "to carry back, bring back" from → re- "back" + gerere "carry, bear."

Barnus, from bar- "on, upon, up," → on-, + nus "to write;" cf. Kurd. (Sor.) nus, nusen "to write;" Lori nisane "to write;" variants of nevis-, neveštan, → write.

registration
  برنوسش   
barnuseš

Fr.: enregistrement   

1) The act or instance of registering.
2) An entry in a register (Dictionary.com).

register; → -tion.

registry
  برنوسه   
barnusé

Fr.: registre   

1) The act of registering; registration.
2) A place where a register is kept; an office of registration.
3) The state of being registered (Dictionary.com).
4) In → computers, a part of the → central processing unit used to store configuration information about the → software installed on a computer.

register + -y.

relativist
  بازانی‌باور   
bâzâni-bâvar

Fr.: relativiste   

An adherent or advocate of relativism.

From → relative + -ist a suffix of nouns.

Adj. from → relativism.

relativistic
  بازانیگی‌مند، بازانیگی‌ور   
bâzânigimand, bâzânivar

Fr.: relativiste   

1) Physics: Relating to the → relativity theory.
2) Philosophy: Involving or characterized by → relativism.
See also:
non-relativistic, → relativistic aberration, → relativistic Doppler effect, → relativistic effect, → relativistic mass, → relativistic particle, → relativistic precession, → relativistic quantum mechanics, → relativistic redshift, → relativistic speed, → relativistic spin precession, → relativistic velocity, → ultrarelativistic, → ultrarelativistic gas.

From → relativist + → -ic.

<< < -is bal cha dis epi gra lin non pis rel spe the > >>