An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1037
  پیرابین، پیرانما   
pirâbin, pirânamâ (#)

Fr.: périscope   

An optical instrument for viewing objects which are above the eye-level of the observer, or are placed so that direct vision is blocked.

peri-; + → -scope.


Fr.: pergélisol   

Layer of soil or rock, at some depth beneath the surface, in which the temperature has been continuously below 0°C from a few to several thousands of years. It exists where summer heating fails to reach the base of the layer of frozen ground.

From perma(nent) + → frost.

Mândbašm, from mând, → permanent, + bašm, → frost.

mândegâr (#)

Fr.: permanent   

Lasting or remaining without essential change.

Permanent, from M.Fr. permanent, from L. permanentem "remaining," pr.p. of permanere "endure, continue, stay to the end," from per- "through" + manere "stay," cognate with Pers. mândan, as below; → gas.

permanent gas
  گاز ِ ماندگار   
gâz-e mândegâr

Fr.: gaz permanent   

Gas which cannot be liquefied by pressure alone; gas above its critical temperature.

permanent; → gas.

permanent magnet
  آهنربای ِ ماندگار   
âhanrobâ-ye mândegâr

Fr.: aimant permanent   

A piece of magnetic material which, having been magnetized, retains a substantial proportion of its magnetization indefinitely.

permanent; → magnet.

permanent memory
  برم ِ ماندگار   
barm-e mândegâr

Fr.: mémoire permanente   

Storage capacity which does not depend on a continuous supply of power, e.g. disks, magnetic tapes, etc.

permanent; → memory.

tarâvâyi (#)

Fr.: perméabilité   

The degree of → magnetization of a material that responds linearly to an applied magnetic field. → magnetic permeability.

From permeable, from L. permeabilis "that can be passed through, passable," from L. permeare "to pass through," from per- "through" + meare "to pass," from PIE base *mei- "to change; to go, move."

Tarâvâyi quality noun of tarâvâ "permeable," from tarâvidan "to exude, trickle, ooze; to drop," probably from Proto-Iranian *tra-vaxš-. The first component *tra- "across, over, beyond," → trans-. The second component *vaxš-, cf. Av. uxš-/vaxš- "to sprinkle," present tense stem uxš-; cf. Skt. uks- "to sprinkle, moisten," uksati "spinkles, wets;" Gk. hygros "wet, moist, fluid;" L. uvidus "watery, humid, damp." Tarâvidan may be a back formation from *tarâvaš.


Fr.: permission   

The act of permitting. Authorization granted to do something.

verbal noun of → permit; → -tion.


Fr.: permettre   

To allow to be done or occur.

From M.Fr. permetre, from L. permittere "give up, allow, allow to pass through," from per- "through;" (from PIE base *per- "through, across, beyond;" cf. Gk. peri "around, about, beyond;" O.Pers. pariy "around, about," Av. pairi "around, over;" Skt. pari; Indo-Iranian *pari- "around;" Mod.Pers. par-, pirâ- "around, about") + mittere "let go, send."

Parzâmidan, literally "to allow to go through," infinitive of parzâm, from par- "through," from O.Pers. pariy "around, about," Av. pairi "around, over," cognet with L. per-, as above + zâm stem of Mid.Pers. zâmenidan "to let go, lead, send," Mod.Pers. gâm "step, pace," âmadan "to come;" O.Pers./Av. gam- "to come; to go," Av. jamaiti "goes;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step," L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come," E. come; PIE base *gwem- "to go, come."


Fr.: permis   

Allowed. → permitted line; → permitted transition.

Past participle of → permit.

permitted line
  خط ِ پرزامیده   
xatt-e parzâmidé

Fr.: raie permise   

An ordinary spectral line emitted by atoms undergoing energy transitions that are allowed by the selection rules of quantum mechanics. → forbidden lines.

permitted; → line.

permitted transition
  گذرش ِ پرزامیده   
gozareš-e parzâmidé

Fr.: transition permise   

A transition between two quantum mechanical states that does not violate the quantum mechanical selection rules.

permitted; → transition.


Fr.: permittivité   

A measure of the ability of a material to transmit (or "permit") an electric field. Permittivity is defined as the ratio of the flux density produced by an electric field in a given dielectric to the flux density produced by that field in a vacuum. In → SI units, permittivity is measured in → farads per meter. The constant ε0 is known as the permittivity of free space; its value is about 8.854 x 10-12 F/m.

State or quality noun from → permit.

  پرموتش، جایگشت   
permuteš, jâygašt

Fr.: permutation   

Math.: A rearrangement of the elements of a set in a particular order, as abc into acb, bac, etc.

Verbal noun of → permute.

Permuteš, verbal noun of → permute.
Jâygašt , from "place" (from Mid.Pers. giyag "place;" O.Pers. ā-vahana- "place, village;" Av. vah- "to dwell, stay," vanhaiti "he dwells, stays;" Skt. vásati "he dwells;" Gk. aesa (nukta) "to pass (the night);" Ossetic wat "room; bed; place;" Tokharian B wäs- "to stay, wait;" PIE base ues- "to stay, live, spend the night") + gašt past tense of gaštan, gardidan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend").


Fr.: permuter   

M.E., from L. permutare "to change throughout," from per- "through" + mutare "to change," from PIE base *mei- "to change, go, move;" cf. Av. miθô "inverted, false," miθaoxta- "wrong spoken;" Skt. methati "changes, alternates, joins, meets," mith- "to alternate, meet," mithás "opposite, in opposition;" L. meare "to go, pass," mutuus "done in exchange;" Goth. maidjan "to change;" E. prefix mis- (in mistake).

Permutidan, from permute, as above.


Fr.: perpendiculaire   

A line or plane at right angles to another line or plane. Two curves are said to be perpendicular if their tangent lines are mutually perpendicular. → normal; → vertical

From M.E. perpendiculer(e), from O.Fr. perpendiculiere, from L. perpendicularis "vertical, as a plumb line," from perpendiculum "plumb line," from perpendere "balance carefully," from per- "thoroughly" + pendere "to weigh, to hang."

Pâlâr "pillar, column, main beam."

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.

hamišegi (#)

Fr.: perpétuel   

Lasting an indefinitely long time; eternal; permanent. → perpetual motion; → perpetual calendar.

M.E. perpetuall, from O.Fr. perpetuel, from L. perpetualis "permanent," from perpetuus "continuous, universal," from perpetis, genitive of Old L. perpes "lasting;"

Hamišegi from hamišé "always;" Mid.Pers. hamišag, from anôšag "immortal," from Av. an-aoša-, from negation prefix → an- + aošah- "death; ruin; corruption" (Mid.Pers. hôš "death;" Mod.Pers. hôš, huš "death; mind; intellect"); cf. derivatives Sogd. nôšé "immortal," nôšak "always;" Mod.Pers. nôš, nuš "the water of immortality; sweet; honey."

perpetual calendar
  گاهشمار ِ همیشگی   
gâhšomâr-e hamišegi

Fr.: calendrier perpétuel   

A chart or mechanical device that indicates the day of the week for any given date over a period of many years.

perpetual; → calendar.

perpetual motion
  جنبش ِ همیشگی   
jonbeš-e hamišegi

Fr.: mouvement perpétuel   

The motion of a hypothetical machine which, once set in motion, will go on for ever without any losses due to → friction or other forms of → dissipation of energy and without receiving any external energy.

perpetual; → motion.

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