An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -ab aba abs abs abs acc acc act act ada adi adv afo agi Ale alg Alk Aln alr alt amb ana And ang ani ano ant ant ape apo app aps arc arg Aro asc ass ast ast asy atm att aur ave axi > >>

Number of Results: 888
pirâ (#)

Fr.: abscisse   

In plane Cartesian coordinates, the distance of any point from the vertical axis (y-axis). The distance from the horizontal axis (x-axis) is called → ordinate.

From L abscissa (linea) "(a line) cut off," from p.p. of abscindere "to cut off," from → ab- "off, away" + scindere "to cut." The word abscissa was first used by Stefano degli Angeli (1623-1697), a professor of mathematics in Rome.

Pirâ, present stem of pirâstan "to prune, clip, trim; to adorn, embellish (especially by cutting, clipping, or taking away)," related to ârâstan "to arrange, adorn," from Mid.Pers. payrâstan, patrâstan "to arrange, adorn," ultimately from Proto-Iranian *pati-rad-. The first component *pati- "to, toward, near to, against;" cf. Mid.Pers. pât-, from O.Pers. paity "against, back, opposite to, toward, face to face, in front of;" Av. paiti; Skt. práti "toward, against, again, back, in return, opposite;" Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti. The second component *rad- "to direct, to prepare;" cf. O.Pers. rād- "to prepare," rās- "to be right, straight, true," rāsta- "straight, true" (Mod.Pers. râst "straight, true"); Av. rāz- "to direct, put in line, set," razan- "order;" Gk. oregein "to stretch out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" Skt. rji- "to make straight or right, arrange, decorate;" PIE base *reg- "move in a straight line."


Fr.: absence   

1) State of being away or not being present.
2) Lack; deficiency.

Noun from → absent.


Fr.: absent   

1) Not in a certain place at a given time; away, missing (opposed to present).
2) Lacking; nonexistent (

M.E., from M.Fr. absent, from L. absentem (nominative absens), p.p. of abesse "to be away from," from → ab- "away" + esse "to be," → present.

Apâst, on the model of L. absentem, as above, from apâ- "away from," → apo-, + ast "is," → present.


Fr.: absent, absentéiste   

A person who is absent, especially from work or school (

From → absent + -ee a suffix forming nouns that denote a person who is the object or beneficiary of the act specified by the verb, from Fr. , ending of p.p.s used as nouns.

Apâstgar, from apâst, → absent, + -gar, → -or.

  اپاستگری، اپاستگرایی   
apâsgari, apâstgerâyi

Fr.: absentéisme   

Voluntary non attendance at work, without valid reason. Absenteeism means either habitual evasion of work, or willful absence as in a strike action. It does not include involuntary or occasional absence due to valid causes, or reasons beyond one's control, such as accidents or sickness (

absent; → -ism.

  ا َوَست   

Fr.: absolu   

1) General: Not limited by restrictions or exceptions; perfect in quality or nature; unqualified in extent or degree; complete.
2) Physics: Relating to measurements or units of measurement derived from fundamental units of length, mass, and time.
3) Physics: Having an ideal value as opposed to a conditional or relative one.
See also: → absolute acceleration, → absolute dating, → absolute humidity, → absolute luminosity, → absolute magnitude, → absolute permeability, → absolute space, → absolute temperature, → absolute tensor, → absolute time, → absolute viscosity, → absolute zero.

From M.Fr. absolut, from L. absolutus "unrestricted," p.p. of absolvere "to set free," from ab- "away" + solvere "to loosen," from PIE *leu-. → solve.

Avast from negation prefix → a- + vast, variant of bast, basté "tied, bound," from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind, → band.

Synonymous: motalq(مطلق), from Ar.

absolute acceleration
  شتاب ِ اوست   
šetâb-e avast

Fr.: accélération absolue   

For a body that moves with respect to a rotating → reference frame, the vector sum of the observed acceleration, the → Coriolis acceleration, and the → centrifugal acceleration. See also the → Coriolis theorem.

absolute; → acceleration.

absolute dating
  سن‌یابی ِ اوست   
senn-yâbi-ye avast

Fr.: datation absolue   

Any method of measuring the age of an event or object in years. For example, in geology, this method can, unlike → relative dating, give us the age of a rock or fossil in x number of years. The most widely used and accepted method of absolute dating is → radioactive dating. See also: → radiocarbon dating, → radiometric dating.

absolute; → dating.

absolute error
  ایرنگ ِ اوست   
irang-e avast

Fr.: erreur absolue   

The difference between the measured value of a quantity x0 and its (true) actual value x, given by Δx = x0 - x. See also: → relative error.

absolute; → error.

absolute humidity
  نمناکی ِ ا َوَست   
namnâki-ye avast

Fr.: humidité absolue   

In a system of moist air, the ratio of the mass of water vapor to the total volume of the system. → humidity.

absolute; → humidity.

absolute luminosity
  تابندگی ِ ا َوَست   
tâbandegi-ye avast

Fr.: luminosité absolue   

A star's → intrinsic brightness, i.e. the total amount of energy radiated by the star per second. → Luminosity is often expressed in units of watts or erg/sec. The Sun's absolute luminosity is 3.86 × 1033 erg/sec.

absolute; → luminosity.

absolute magnitude
  بُرز ِ ا َوَست   
borz-e avast

Fr.: magnitude absolue   

1) The → magnitude a star would have if it were at a distance of 10 → parsecs in a void space, without → interstellar absorption. The absolute magnitude is usually deduced from the → visual magnitude, measured through a V filter (→ UBV system), when it is written as MV. If it is defined for another wavelength, it gets another index (U, B, etc). If the radiation on all wavelengths is included, it becomes absolute → bolometric magnitude, Mbol. The Sun has the absolute magnitude + 4.8. Most of the stars have absolute magnitudes ranging between -9 (→ supergiants) and + 19 (→ red dwarfs) (M.S.: SDE).
2) The brightness a → comet or → asteroid would have if it were at a distance of 1 → astronomical unit both from the Sun and the Earth and were completely illuminated by the Sun (M.S.: SDE).

absolute; → magnitude.

absolute measurement
  اندازه‌گیری ِ اوست   
andâzegiri-ye avast

Fr.: mesure absolue   

A measurement in which the comparison is directly with quantities whose units are basic units of the system. For example, the measurement of speed by measurements of distance and time is an absolute measurement, but the measurement of speed by a speedometer is not an absolute measurement. Note that the word absolute measurement implies nothing about → precision or → accuracy (IEEE Standard Dictionary of Electrical and Electronics Terms).

absolute; → measurement.

absolute permeability
  تراوایی ِ اوست   
tarâvâyi-ye avast

Fr.: perméabilité absolue   

magnetic permeability.

absolute; → permeability.

absolute space
  فضای ِ اوست   
fazâ-ye avast

Fr.: espace absolu   

A fixed space in which physical phenomena occur and whose properties do not depend on what occupies it, nor on the observer. It is a distinguished frame of reference that could show bodies to be truly moving or truly at rest. Absolute space is one of the basic assumptions of → Newtonian mechanics, but it was abandoned in Einstein's → special relativity. See also → absolute time; → space-time.

absolute; → space.

absolute temperature
  دما‌ی ا َوَست   
damâ-ye avast

Fr.: température absolue   

The value of a → temperature in the → Kelvin scale. The absolute temperature is equal to the temperature on the → Celsius scale -273.16 °C.

absolute; → temperature.

absolute tensor
  تانسور ِ اوست   
tânsor-e avast

Fr.: tenseur absolu   

A → tensor of → weight  → zero.

absolute; → tensor.

absolute time
  زمان ِ اوست   
zamân-e avast

Fr.: temps absolu   

A universal time supposed to be the same for all observers at any place in the Universe. Absolute time is one of the foundations of → Newtonian mechanics, but it fails to account for physical phenomena in → reference frames with relative motion. Its abandoning was one of the starting points of → special relativity. See also → absolute space; → space-time.

absolute; → time.

absolute value
  ارزش ِ اوست   
arzeš-e avast

Fr.: valeur absolue   

For any → real number a, the non-negative value of a without regard to its sign; denoted by |a|. Same as → modulus. The absolute value of a is always either → positive or → zero, but never negative. The absolute value of a number may be thought of as its → distance from zero. The following rules hold:
|ab| = |a||b|
|a + b|  ≤  |a| + |b|
|a - b|  ≥  |a| - |b|
For a> 0, |x|  ≤  a if and only if -a  ≤  x  ≤  a.

absolute; → value.

absolute viscosity
  وشکسانی ِ اوست   
vošksâni-ye avast

Fr.: viscosité absolue   

Same as → viscosity and → dynamic viscosity.

absolute; → viscosity.

<< < -ab aba abs abs abs acc acc act act ada adi adv afo agi Ale alg Alk Aln alr alt amb ana And ang ani ano ant ant ape apo app aps arc arg Aro asc ass ast ast asy atm att aur ave axi > >>