An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1043
fizikdân (#)

Fr.: physicien   

A specialist in → physics.

From physic, → physics, + → -ist.

Fizikdân, from fizik, → physics, + -dân "knower," present stem of dânestan "to know," → science.

fizik (#)

Fr.: physique   

The science that deals with matter and energy and their interactions.

M.E. fisyk(e), phisik(e), from O.Fr. fisique, from L. physica (fem. sing.) "study of nature," from Gk. physike episteme "knowledge of nature," from fem. of physikos "pertaining to nature," from physis "nature," from phyein "to bring forth, produce, make to grow," Gk. phy- "to become;" L. fui "I was," futurus "that is to be, future;" Ger. present first and second person sing. bin, bist; E. to be; O.Ir. bi'u "I am;" Lith. bu'ti "to be;" Rus. byt' "to be."

Loan from Fr. physique, as above.


Fr.: physisorption   

A kind of → adsorption in which the forces involved are → intermolecular  → van der Waals forces. Same as → physical adsorption. See also → chemisorption.

Physi-, from → physical; → sorption.

pi number
  عدد ِ پی   
adad-e pi (π)

Fr.: nombre pi (π)   

Symbol, π, for the ratio of the circumference of a circle to its diameter in Euclidean geometry; a fundamental mathematical constant, equal to 3.14159... π is an → irrational number (Lambert, 1761) and also a → transcendental number (von Lindemann, 1882). The most accurate determination of π prior to the Scientific Revolution belongs to the Iranian mathematician Jamshid Kashani, who gave 16 correct decimal places in A.D. 1424. With the advent of → calculus and more recently the invention of powerful computers, the decimal representation of π has now been computed to more than 1012 digits.

The π notation, representing the first letter of the Gk. word περιμετρον → perimeter, was first used by the British mathematician William Jones (1675-1749) in 1706. Its use was generalized after its adoption by the Swiss mathematician Leonard Euler (1707-1783) in 1737; → number.

Piazzi's Flying Star
  ستاره‌ی ِ پرنده‌ی ِ پیاتزی   
setâre-ye parande-ye Piazzi

Fr.: étoile volante de Piazzi   

Same as → 61 Cygni and → Bessel's star.

Giuseppe Piazzi (1746-1826) was the first to notice the large → proper motion of the star, in 1804. His observations over a period of 10 years revealed the largest proper motion ever detected for any star at the time, leading him to baptize it the "Flying Star;" → fly; → star.

Pickering series
  سری ِ پیکرینگ   
seri-ye Pikering (#)

Fr.: série de Pickering   

A series of → spectral lines of → singly ionized helium, observed in very hot → O-type and → Wolf-Rayet stars associated with transitions between the → energy level with → principal quantum number n = 4 and higher levels: n = 4-5 (10124 Å), n = 4-7 (5412 Å), n = 4-9 (4541 Å), n = 4-9 (4522 Å), and n = 4-11 (4200 ˚). The 4-6 (6560 Å) and 4-8 (4859 Å) transitions were originally not included in this series because they coincided with the hydrogen → Balmer series of lines and were thus obscured.

In honor of Edward C. Pickering (1846-1919), American astronomer and physicist; → series.

piko- (#)

Fr.: pico-   

A prefix denoting 10-12.

From It. piccolo "small."

Negârgar (#)

Fr.: Peintre   

The Painter's Easel. A faint constellation in the southern hemisphere, at 5h 30m right ascension, 50° south declination. Its brightest star is of magnitude 3.2. Its second brightest star, → beta Pictoris, is famous for its → circumstellar disk of gas and dust. Abbreviation: Pic; genitive: Pictoris.

Pictor, short for Equuleus Pictoris "painter's easel," from L. pictor "painter," from pingere "to make pictures."

Negârgar "painter," from negâr present stem of negâštan "to paint," negâr "picture, figure," from prefix ne- "down; into" (O.Pers./Av. ni- "down; into;" cf. Skt. ni "down," nitaram "downward;" Gk. neiothen "from below;" E. nether; O.E. niþera, neoþera "down, downward, below, beneath," from P.Gmc. *nitheraz; Du. neder; Ger. nieder; PIE *ni- "down, below") + gâr, from kar-, kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make").

fartur (#)

Fr.: image   

Any visible image, however produced. → photograph.

From L. pictura "painting," from pictus, p.p. of pingere "to make pictures, to paint."

Fartur "picture, image; reflexion, inversion" (Dehxodâ, Steingass); maybe from partow, → ray.

tekké (#)

Fr.: pièce, morceau, tache   

1) A portion of an object or of material, produced by cutting, tearing, or breaking the whole.
2) An item forming part of a set.
3) A written, musical, or artistic creation (

M.E. pece, peece, from O.Fr. piece, from V.L. *pettia, probably from Gaulish (cf. Welsh peth "thing;" Breton pez "piece").

Teké "piece, patch."


Fr.: par morceaux   

Denoting a → function that is defined on a sequence of → intervals or pieces. For example: |x| = -x for x < 0, x = 0 for x = 0, and x = x for x > 0.

piece, + -wise, → clockwise.

piecewise continuous function
  کریای ِ پیوسته‌ی ِ تکه‌ای   
karyâ-ye peyvaste-ye tekke-yi

Fr.: fonction continue par morceaux   

A function f(x) in an interval if :1) the interval can be divided into a finite number of pieces in each of which f(x) is continuous, and 2) the limits of f(x) as x approaches the boundary point of each piece are finite. In other words, a piecewise continuous function is one that is made up of a finite number of continuous pieces.

piecewise; → continuous; → function.

piezoelectric effect
  اُسکر ِ فشاربرقی   
oskar-e fešârbarqi

Fr.: effet piézoélectrique   

The property exhibited by some crystals (notably quartz) that develop an electric charge or potential difference across them when subjected to mechanical strain; and conversely produce mechanical forces when a voltage is applied to them in a suitable manner.

From piezo-, from Gk. piezein "to press tight" + → electric; → effect.

oskar, → effect; fešârbarqi pertaining to fešârbarq, from fešâr, → pressure, + barq, → electricity.

tal (#)

Fr.: pile   

An assemblage of things laid or lying one upon the other (

M.E., from M.Fr. pile and directly from L. pila "pillar, mole of stone."

Tal "heap; hill," maybe related to Gk. tylos "a hard and thickened area on the skin, callus, lump," tymbos "burial mound, grave, tomb;" Av. tuma- "fat;" L. tumere "to swell," tumulus "raised heap of earth," tumidus "swollen;" tumor "a swelling."

sotun (#)

Fr.: pilier   

An elongated structure often found at the interface between an → H II region and its associated → molecular cloud. Also called → elephant trunk. The most famous examples are the "pillars of creation" in the → Eagle Nebula, which are several → light-years in length. There are indications for star formation at the tips of the pillars. In general the pillars point like fingers toward the young → massive stars ionizing the nebula. Most of the mass is concentrated in the head which has a bright rim facing the young stars.

M.E. pillare, O.Fr. piler, from M.L. pilare, from L. pila "pillar, stone barrier."

Sotun "pillar," → column.

âsé (#)

Fr.: axe   

The component of a → planispheric astrolabe that is inserted in the back of the → mater. The pin enables the main parts of the instrument (the → alidade, the → rete, and the → rule) to rotate freely around the common center of the mater and the → tympanum (online museo galileo, VirtualMuseum).

M.E. pinne, from O.E. pinn "peg, bolt," from L. pinna "a feather, plume."

&ACIRC;sé, → axis.


Fr.: effet de striction   

The constriction of a current-carrying plasma column caused by its external self-magnetic field.

M.E. pinch, from O.Fr. pincier "to pinch," possibly from V.L. *punctiare "to pierce," from L. punctum "point," and *piccare "to pierce."

Penk "pinch, squeezing or compressing between the finger and thumb" (Dehxodâ), cf. (Tabari) pendik, pecelik, (Kermâni) perenju "pinch," maybe related to panjé "the palm of the hand with five fingers; fist," from panj "five," from Mid.Pers. panj; Av. panca; cf. Skt. pánca; Gk. pente; L. quinque; O.E. fif, from P.Gmc. *fimfe (O.S. fif, O.H.G. funf); from PIE base *penkwe "five."

pincushion distortion
  چولگی ِ بالشتکی   
cowlegi-ye bâleštaki

Fr.: distorsion en coussinet   

An → aberration of a → lens  → system in which → magnification increases with → distance from the → optical axis, whereby → horizontal and → vertical lines bend inward toward the → center of the → field. Opposite of → barrel distortion.

Pincushion, from pin, from M.E. pinne, O.E. pinn "peg;" cf. D. pin, Ger. Pinne; perhaps from L. pinna "feather, quill" + cushion, M.E. cuisshin, O.Fr. coissin (Fr. coussin) a variant of V.L. *coxinum, either from L. coxa "hip, thigh," or from L. culcita "mattress;" → distortion.

Cowlegi, → distortion; bâleštaki, adj. of bâleštak, diminutive of bâlešt, variant bâleš "cushion, pillow," Mid.Pers. bâlišn, bâlên "cushion, pillow;" Av. barəiš- "pillow, cushion;" cf. Skt. barhis- "straw, a bed or layer of kusa grass strewed over the sacrificial ground."

mori (#)

Fr.: pinnule   

In a → planispheric astrolabe, a vane on an end of an → alidade with a hole, slot, or other indicator through which one can view a distant object. There may also be a pointer or pointers on the alidade to indicate a position on a scale.

Diminutive of L. pinna "feather, wing, fin;" + → -ule.

Mori (Biruni).

ferferé (#)

Fr.: moulin à vent   

A child's toy consisting of a wheel or leaflike curls of paper or plastic loosely attached by a pin to a stick, designed to revolve when blown by or as by the wind (

pin; → wheel.

Ferferé "pinwheel," of unknown origin.

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