An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 16 Search : relative

Fr.: relatif   

(adj.): Existing or having its specific nature only by relation to something else; not absolute or independent.
See also: → relative atomic mass, → relative azimuth, → relative dating, → relative density, → relative error, → relative frequency, → relative humidity, → relative invariant, → relative tensor, → relative vector, → relative permeability, → relative refractive index, → relative sunspot number, → relative velocity, → relatively, → relativity.

From M.E. relatif (n.), from O.Fr. relatif, from L.L. relativus "having reference or relation," from L. relatus, suppletive p.p. of referre "to refer," → relate.

Bâzâni, from bâzân- present stem of bâzânidan, → relate, + -i adj. suffix.

relative atomic mass
  جرم ِ اتمی ِ بازانی   
jerm-e atomi-ye bâzâni

Fr.: masse atomique relative   

The ratio of the mass of an atom of the → chemical element to one-twelfth the mass of an atom of carbon-12. Because an element in nature is usually a mixture of isotopes, the relative atomic mass is also the weighted mean of the atomic masses of all the atoms in a particular sample of the element, weighted by isotopic abundance. In this sense, relative atomic mass was once known as → atomic weight.

relative; → atomic; → mass.

relative azimuth
  سوگان ِ بازانی   
sugân-e bâzâni

Fr.: azimut relatif   

The difference in → azimuth between the → Moon and the → Sun.

relative; → azimuth.

relative dating
  سن‌یابی ِ بازانی   
senn-yâbi-ye bâzâni

Fr.: datation relative   

A method of dating that can only tell us whether an event or object is older or younger than another event or object. In geology, different layers of rock are compared to determine an ordered sequence of events in geologic history. In contrast to → absolute dating, relative dating cannot give the actual age of a rock. See also → stratigraphy.

relative; → dating.

relative density
  چگالی ِ بازانی   
cagâli-ye bâzâni

Fr.: densité relative   

The ratio of the density of a substance to the density of a given reference material. For a solid or liquid, it is the density (at 20°C) relative to the maximum density of water (at 4°C). For a gas is its density divided by the density of hydrogen (or sometimes dry air) at the same temperature and pressure. Also called → specific density.

relative; → density.

relative error
  ایرنگ ِ بازانی   
irang-e bâzâni

Fr.: erreur relative   

The → absolute error divided by the true value x, that is: Δx/x. The result may be expressed as a percentile and is useful when we want to determine the error relative to the value of the exact quantity.

relative; → error.

relative frequency
  بسامد ِ بازانی   
basâmad-e bâzâni

Fr.: fréquence relative   

Statistics: The number of the occurrences of an event divided by the number of observations.

relative; → frequency.

relative humidity
  نم ِ بازانی   
nam-e bâzâni

Fr.: humidité relative   

The amount of moisture in the air compared to what the air can "hold" at that temperature. It is given by the ratio of the partial pressure of water vapor in the mixture to the saturated vapor pressure of water at a specific temperature.

relative; → humidity.

relative invariant
  ناورتای ِ بازانی   
nâvartâ-ye bâzâni

Fr.: invariant relatif   

A → relative tensor of order zero.

relative; → invariant.

relative permeability
  تراوایی ِ بازانی   
tarâvâyi-ye bâzâni

Fr.: perméabilité relative   

magnetic permeability.

relative; → permeability.

relative refractive index
  دیشن ِ شکستی ِ بازانی   
dišan-e šekasti-ye bâzâni

Fr.: indice de réfraction relatif   

The ratio of the sine of the angle of incidence to the sine of the angle of refraction for a ray passing out of one of the media into the other.

relative; → refractive; → index.

relative sunspot number
  شمار ِ بازانی ِ هورلک   
šomâr-e bâzâni-ye hurlak

Fr.: nombre relatif de taches solaires   

Same as → Wolf number and → sunspot number.

relative; → sunspot; → number.

relative tensor
  تانسور ِ بازانی   
tânsor-e bâzâni

Fr.: tenseur relatif   

A generalized tensor concept that is characterized by a → Jacobian matrix of transformation raised to a power called → weight of a tensor density. In practice, only relative tensors of weight 1 or -1 are used. The product of a relative tensor of weight -1 by another tensor of weight 1 is an → absolute tensor. Same as → tensor density.

relative; → tensor.

relative vector
  بردار ِ بازانی   
bordâr-e bâzâni

Fr.: vecteur relatif   

A → relative tensor of → order  → one.

relative; → vector.

relative velocity
  تندای ِ بازانی   
tondâ-ye bâzâni

Fr.: vitesse relative   

For two objects A and B, the velocity which B, supposing itself at rest, assigns to A.

relative; → velocity.

  بازانی‌وار، بازانانه   
bâzânivâr, bâzânâné

Fr.: relativement   

In a relative manner; in relation to something else.

From → relative + -ly "-vâr, -âné."