An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 383

Fr.: opportunité   

1) An appropriate or favorable time or → occasion.
2) A situation or condition favorable for attainment of a goal (

opportune + → -ity.


Fr.: s'opposer à, faire opposition à; opposer   

1) To act against or provide resistance to.
2) To stand in the way of; hinder; obstruct (

M.E., from O.Fr. oposer "to oppose, resist; contradict," from poser "to place, lay down," blended with L. opponere "to oppose, to object," → position.

Pâdistidan, infinitive from pâdist, → opposition.

  ۱) رو-به-رو؛ ۲) پادیستین؛ ۳) پادچم   
1) ru-be-ru; 2) pâdistin; 3) pâdcem

Fr.: 1) opposé, d'en face; 2) contraire, opposé; 3) antonyme   

1) Situated, placed, or lying face to face with something else or each other, or in corresponding positions with relation to an intervening line, space, or thing: opposite ends of a room (
2) Contrary or radically different in some respect common to both, as in nature, qualities, direction, result, or significance; opposed (
3) An → antonym.

M.E., from M.Fr., from L. oppositus, p.p. of opponere, → opposition.

1) Ru-be-ru "face to face," → surface.
2) Pâdistin, from pâdist, → opposition, + -in, as in zirin, zebarin, pišin, pasin.
3) Pâdcem, → antonym.

  ۱، ۲) پادیست؛ ۳، ۴) پادیستان   
1, 2) pâdist; 3, 4) pâdistân

Fr.: opposition   

1) The action of opposing, resisting, or combating.
2) A person or group of people opposing, criticizing, or protesting something, someone, or another group (
3) The position of a solar system body having its orbit outside that of the Earth when the Earth is in a line between the Sun and the body. At opposition the body has a solar → elongation of 180°, and is closest to the Earth. It will, in principle, be visible throughout the night. It will rise in the east as the Sun sets in the west and it will set as the Sun rises. This is because, at opposition, the body and the Sun are 12 hours apart. The inner planets can never be in opposition. The opposite of opposition is → conjunction.
4) Two periodic quantities of the same frequency are said to be in opposition when the → phase difference between them is one half of a → period.

Verbal noun of → oppose.

Pâdist "standing against," from pâd- "agaist, contrary to," → anti-, + ist present stem of istâdan "to stand" (Mid.Pers. êstâtan, O.Pers./Av. sta- "to stand; to set;" Av. hištaiti; cf. Skt. sthâ- "to stand;" Gk. histemi "put, place, weigh," stasis "a standing still;" L. stare "to stand;" Lith. statau "place;" Goth. standan; PIE base *sta- "to set, stand").
Pâdistân, from pâdist + -ân suffix of place and time.


Fr.: opter   

To make a choice; choose (usually followed by for).

From Fr. opter "to choose," from L. optare "to choose, desire, wish for," from L. optare "to desire, choose," from PIE root *op- "to choose, prefer."

Optidan, from L. optare, as above.

  اپتانه، اپتمند   

Fr.: optatif   

Of, relating to, or constituting a verbal mood that is expressive of wish or desire.

From M.Fr. optatif, from L. optativus, from optatus, p.p. of optare, → opt, + -ivus, → -ive.

Optâné, optmand, from opt present stem of optidan, → opt, + adj. suffixes -âné, -mand. -yi.

  ۱) نوری، نوریک؛ ۲) دیدگانی   
1) nuri, nurik; 2) didgâni

Fr.: optique   

1) Of or pertaining to the eye or sight.
2) Same as → optical.

From M.Fr. optique, from M.L. opticus "of sight or seeing," from Gk. optikos "of or having to do with sight," from optos "seen, visible," from op-, root of opsesthai "be going to see," related to ops "eye," from PIE *okw- "eye/see."

1) Nuri, nurik, from nur, → light + -i, -ik adj. suffix → -ic.
2) Didgâni, related to didgân "eyes," plural of didé "eye; seen," from didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").

optic axis
  آسه‌یِ نوری   
âse-ye nuri

Fr.: axe optique   

The direction in a doubly refracting crystal in which light is propagated without double refraction.

optic; → axis.

  ۱) نوری، نوریک؛ ۲) دیدگانی   
1) nuri, nurik; 2) didgâni

Fr.: optique   

1) Of, pertaining to, or applying optics or the principles of optics.
2) Of or pertaining to sight or vision; visual; of or pertaining to the eye.

From → optic + → -al.


optical aberration
  بیراهشِ نوری   
birâheš-e nuri

Fr.: aberration optique   

An imperfection in the imaging properties of a lens or mirror. The main aberrations are → chromatic aberration, → spherical aberration, → coma, → astigmatism, → field curvature, → distortion.

optical; → aberration.

optical activity
  ژیرندگیِ نوری   
žirandegi-ye nuri

Fr.: activité optique   

The property possessed by some substances and their solutions of rotating the plane of vibration of → polarized light. When a beam of → linearly polarized light is sent through an optically active substance, such as crystalline quartz and sugar solution, the direction of vibration of the emerging linearly polarized light is found to be different from the original direction. Those which rotate the → plane of polarization to the right, for an observer looking in the incoming beam, are called → dextrorotatory or right handed; those which rotate it to the left, → levorotatory or left handed. Optical activity may be due to an asymmetry of molecules of a substance (solutions of cane sugar) or it may be a property of a crystal as a whole (crystalline quartz).

optical; → activity.

optical analysis
  آنالسِ نوری   
ânâlas-e nuri

Fr.: analyse optique   

The mathematical evaluation of an optical system to determine its basic optical properties and image quality characteristics.

optical; → analysis.

optical autocorrelator
  خودهم‌باز‌آنگرِ نوری   
xod-hambâzângar-e nuri

Fr.: autocorrélateur optique   

An instrument used to test lenses by utilizing the → optical transfer function. It consists of a HeNe laser, a beamsplitter and two mirrors.

optical; → autocorrelator.

optical axis
  آسه‌یِ نوری   
âse-ye nuri (#)

Fr.: axe optique   

Line passing through the optical center and the center of curvature a spherical mirror or lens.

optical; → axis.

optical bench
  میز ِ نوریک، ~ نورشناختی   
miz-e nurik, ~ nuršenâxti

Fr.: banc optique   

A track or table on which sources, lenses, mirrors, and other optical components can be mounted and moved. It is used in optics experiments.

optical; bench, M.E., from O.E. benc "long seat;" cf. Da. bænk, M.Du. banc, O.H.G. banch.

Miz "table," originally "preparations for entertaining a guest; guest;" Mid.Pers. mêzd "offering, meal;" nurik, nuršenâxti, → optical.

optical center
  مرکزِ نوری   
markaz-e nuri (#)

Fr.: centre optique   

Of a thin lens, a point situated at the geometrical center of the lens, through which an incident ray passes without being deviated.

optical; → center.

optical component
  همنه‌ی ِ نوریک   
hamne-ye nurik

Fr.: composante optique   

Any device such as a → lens, → prism, → mirror, and/or other similar objects used in an → optical system.

optical; → component.

optical counterpart
  همتایِ نوری   
hamtâ-ye nuri

Fr.: contrepartie optique   

An object with usually weak emission in the visible found to be the optical representation of an object which radiates chiefly in other electromagnetic wavelength ranges.

optical; counterpart, from O.Fr. contrepartie, from contre "facing, opposite," → counter-, + partie "copy of a person or thing," originally feminine p.p. of partir "to divide."

Hamtâ "counterpart, resembling, equal," from ham- "together, with; same, equally, even" (Mid.Pers. ham-, like L. com- and Gk. syn- with neither of which it is cognate. O.Pers./Av. ham-, Skt. sam-; also O.Pers./Av. hama- "one and the same;" Skt. sama-; Gk. homos-; originally identical with PIE numeral *sam- "one," from *som-. The Av. ham- appears in various forms: han- (before gutturals, palatals, dentals) and also hem-, hen-) + "fold, plait, ply; piece, part," also a multiplicative suffix; Mid.Pers. tâg "piece, part;" nuri, → optical.

optical density
  چگالیِ نوری   
cagâli-ye nuri

Fr.: densité optique   

The transmittance of a point on a photographic negative equal to the log to the base 10 of the reciprocal of the transmittance through the negative at that point.

optical; → density.

optical depth
  ژرفایِ نوری   
žarfâ-ye nuri

Fr.: profondeur optique   

1) A measure of how much radiation is absorbed when traveling through a medium (such as the atmosphere of a star or the interstellar medium) from the source to a given point. It depends on the type of medium and the frequency of radiation. It is defined as a dimensionless quantity λ = κλ ρ dx, where κλ is the extinction coefficient, ρ the density, and dx the path length.
2) The ratio of the intensity of radiation (light or radio waves) incident on a ring to that emerging from the opposite face of the ring, expressed as a natural logarithm. If the reduction in intensity is by a factors of e (= 2.718), the ring is said to have an optical depth of 1. Normal (or normalized) optical depth is optical depth corrected for oblique (non-vertical) viewing. In ring studies, the terms optical depth and optical thickness are generally used interchangeably. These terms generally refer to a particular wavelength (Ellis et al., 2007, Planetary Ring Systems, Springer).

optical; → depth.

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