An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 23 Search : axis
axis
  آسه   
âsé (#)

Fr.: axe   

1) One of the principal lines through the center of a figure or a solid, especially, the line which divides the figure or solid symmetrically.
2) A fixed line along which distances are measured or to which position are referred.

L. axis "axle, pivot," akin to O.E. eax "axis, axle," Gk. axon "axle," Skt. aksa- "axle, axis, beam of a balance;" PIE base *aks- "axis."

Âsé, from Pers. dialects: Qâyeni asak "the shaft connecting the plough to the yoke," Lori esi "a pillar (used to put up a tribal tent)," variants hosi, hosin, Tabari âssen "the foot of a door on which it turns," cf. Skt. ISA- "pole or shafts of a carriage or plough," Av. aêša "the two shafts," Mod.Pers. xiš "plough(share)," Gk. oiax "handle of rudder, tiller, helm," PIE base *ei-, *oi- "pole, thill."

axis of rotation
  آسه‌ی ِ چرخش   
âse-ye carxeš

Fr.: axe de rotation   

Same as → rotation axis and → rotational axis.

axis; → rotation.

axisymmetric
  همامون ِ آسه‌ای، آسه-همامون   
hamâmun-e âse-yi, âse-hamâmun

Fr.: axisymétrique   

Having → axisymmetry.

axisymmetry
  همامونی ِ آسه‌ای، آسه-همامونی   
hamâmuni-ye âse-yi, âse-hamâmuni

Fr.: axisymétrie   

Same as → axial symmetry.

celestial axis
  آسه‌ی ِ آسمانی   
âse-ye âsmân (#)

Fr.: axe du monde   

The Earth's axis extended to the → celestial pole.

celestial; → axis.

conjugate axis
  آسه‌ی ِ همیوغ   
âse-ye hamyuq

Fr.: axe conjugué   

One of the two diameters of a conic, so related that a tangent at the end of one is parallel to the other.

conjugate; → axis.

declination axis
  آسه‌ی ِ واکیلش   
âse-ye vâkileš

Fr.: axe de déclinaison   

The axis to which the telescope tube is fastened in an → equatorial mounting.

declination; → axis.

inclination of axis
  درکیل ِ آسه   
darkil-e âse

Fr.: inclinaison de l'axe   

The angle between the rotation axis of a planet and the normal to the ecliptic.

inclination; → axis.

magnetic axis
  آسه‌ی ِ مغناتیسی   
âse-ye meqnâtisi

Fr.: axe magnétique   

The imaginary straight line joining the two → poles of a → magnet.

magnetic; → meridian.

major axis
  آسه‌ی ِ مهین   
âse-ye mehin

Fr.: grand axe   

The greatest diameter of an ellipse; it passes through the two foci.

major; → axis.

minor axis
  آسه‌ی ِ کهین   
âse-ye kehin

Fr.: petit axe   

The axis of an ellipse that is perpendicular to the major axis at a point equidistant from the foci.

minor; → axis.

off-axis optical system
  راژمان ِ نوریک ِ اپ-آسه   
râžmân-e nurik-e ap-âsé

Fr.: système optique hors axe   

An → optical system in which the → optical axis of the → aperture is not coincident with the mechanical center of the aperture.

off; → axis; → optical; → system.

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.

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.

orbital axis
  آسه‌ی ِ مداری   
âse-ye madâri

Fr.: axe orbital   

The → perpendicular to the → orbital plane.

orbital; → axis.

parallel axis theorem
  فربین ِ آسه‌ها‌ی ِ پراسو   
farbin-e âsehâ-ye parâsu

Fr.: théorème des axes parallèles   

The → moment of inertia of a body about any given axis is the moment of inertia about a parallel axis through the center of mass, plus the moment of inertia about the given axis if the mass were located at the center of mass. same as → Steiner's theorem.

parallel; → axis; → theorem.

perpendicular axis theorem
  فربین ِ آسه‌ها‌ی ِ پالار   
farbin-e âsehâ-ye pâlâr

Fr.: théorème des axes perpendiculaires   

The → moment of inertia of a plane object (→ lamina) about an axis perpendicular to the plane is equal to the sum of the moments of inertia about any two perpendicular axes in the plane. Thus if x and y axes are in the plane, Iz = Ix + Iy.

perpendicular; → axis; → theorem.

polar axis
  آسه‌ی ِ قطبی   
âse-ye qotbi (#)

Fr.: axe polaire   

The axis of an → equatorial mounting that is parallel to the Earth's axis, and consequently points to the celestial pole.

polar; → axis.

praxis
  ورزیدار   
varzidâr

Fr.: praxis   

1) The practice and practical side of knowledge or skills, as opposed to the → theory.
2) Accepted practice or custom.

M.L. praxis "practice, action," from Gk. praxis "practice, action, doing," from stem of prassein "to do, to act."

Varzidâr, from varzid past stem of varzidan, → practice, + -âr prefix forming nouns of action, such as kerdâr, raftâr, didâr, goftâr, jostâr, etc.

radical axis
  آسه‌ی ِ پایه   
âse-ye pâyé

Fr.: axe radical   

Of two circles, the straight line containing all points P such that the lengths of the tangents from P to the two circles are equal.

radical; → axis.

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