An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 397
oqyânus-šenâsi (#)

Fr.: océanographie   

The study of the ocean, embracing and integrating all knowledge pertaining to the ocean's physical boundaries, the chemistry and physics of sea water, and marine biology.

ocean + → -graphy.

Oqyânusocean + -šenâsi-logy.

oxrâ (#)

Fr.: ocre   

Any of various natural clays rich in ferric oxides (Fe2O3) and containing silica and alumina. Used as a red (→ hematite) or yellow (→ limonite) pigment.

M.E. oker, O.Fr. ocre, from L. ochra, from Gk. okhra, from okhros "pale yellow."

Oxrâ, loan from Gk.

Ockham's razor
  اُستره‌ی ِ آکم   
ostare-ye Ockham (#)

Fr.: rasoir d'Ockham   

The notion that any hypothesis should be stripped of all unnecessary assumptions. If two hypotheses fit the observations equally well, the one that makes the fewest assumptions should be chosen.

The doctrine was formulated by William of Ockham (c.1288-c.1347), an English Franciscan friar and scholastic philosopher. Razor from O.Fr. rasour "a razor," from raser "to scrape, shave."

Ostaré "razor," from sotordan "to shave, erase, remove;" Mid.Pers. ôstarak "removed, shaved," ôstârišn "wiping, shaving;" cf. Khotanese ustar- "to remove," Sogdian (prefixed *pari-) prtr- "to wipe off, dry up," from Proto-Iranian *us-tar- "to remove, wipe off."

octa-, oct-
  هشت-، اکتا-، اکت-   
hašt-, octa-, oct-

Fr.: octa-, octo-, oct-   

A prefix meaning eight.

From L. octo, Gk. okto, cognate with Pers. hašt, as below. Skt. asta, Goth. ahtau, O.E. eahta (see eight).

Hašt "eight," from Mid.Pers. hašt, O.Pers.*aštahva- "eighth;" Av. ašta; cf. Skt. astā; Ossetic ast; (Buddhist) Sogdian 'št; Gk. okto, L. octo (Fr. huit; Sp. ocho); P.Gmc. *akhto(u) (O.E. eahta, æhta, E. eight, O.N. atta, Ger. acht, Goth. ahtau); PIE base *oktô(u).
Octa-, oct, loaned Gk. forms, as above.


Fr.: octade   

A group of eight units or figures.
Chemistry: An element, atom, or group having a valence of eight.

From Gk. oktad- (stem oktás) "group of eight," from okt-oct- + -ad a prefix denoting a group or unit comprising a certain number, sometimes of years (e.g. dyad; triad).

  هشت‌بر، هشت‌گوش   
haštbar, haštguš (#)

Fr.: octogone   

A polygon having eight angles and eight sides.

From L. octagonos, from Gk. oktagononos "eight-angled," from okta-, → octa-, oct- "eight," + gonia "angle," related to gony "knee," L. genu "knee," cuneus "a wedge;" Av. žnu- "knee;" Mod.Pers. zânu "knee," Skt. janu- "knee," kona- "angle, corner;" PIE base *g(e)neu-, see below.

Haštbar "eight-sided," from hašt "eight," → octa-, oct- + bar "side; breadth; breast" (Mid.Pers. var "breast;" Av. vouru "wide, broad, extended" (vourucašāni- "looking far"), related to varah- "breast;" cf. Skt. urú- "wide, broad," úras- "breast;" Gk. eurus "wide, broad;" PIE base uer-, ueru-s"wide, broad"); haštguš, from hašt, → octa-, oct-, + guš "corner, angle," Mid.Pers. gošak "corner."


Fr.: octaèdre   

A geometric solid with eight sides.

octa-, oct-; → -hedron.

Haštakân (#)

Fr.: Octant   

The Octant. A faint and obscure constellation, at 21h right ascension, 80° south declination, containing the south celestial pole. Its star Sigma Octantis is the closest naked-eye star to the pole, but it is so faint (magnitude 5.47) that it is practically useless as a polar star for navigation purposes. Abbreviation: Oct; Genitive: Octantis. It was introduced by the French astronomer Nicolas Louis de Lacaille (1713-1762).

From L.L. octans "eighth part of a circle," from → octa-, oct- + -ans, as in quadrans; → quadrant.

Haštakân, → octant.

haštakân (#)

Fr.: octant   

1) A portion of a circle cut off by an arc and two radii at 45°, one-eighth of the area of a circle.
2) A instrument incorporating a telescope, the predecessor of the → sextant, used to measure angular distances, mainly in nautical astronomy. It spanned an angular range of 45°.

From L.L. octans "eighth part of a circle," from → octa-, oct- + -ans, as in quadrans; → quadrant.

Haštakân, from haštak "one-eigth," from hašt "eight" (Mid.Pers. hašt, O.Pers.*aštahva- "eighth;" Av. ašta; cf. Skt. astā; Ossetic ast; (Buddhist) Sogdian 'št; Gk. okto, L. octo (Fr. huit; Sp. ocho); P.Gmc. *akhto(u) (O.E. eahta, æhta, E. eight, O.N. atta, Ger. acht, Goth. ahtau); PIE base *oktô(u) + -ak, contraction of yak "one," (Mid.Pers. êwak (Proto-Iranian *aiua-ka-); O.Pers. aiva- "one, alone;" Av. aēuua- "one, alone" (cf. Skt. éka- "one, alone, single;" Gk. oios "alone, lonely;" L. unus "one;" E. one) + -ân nuance suffix.

octâv (#)

Fr.: octave   

The interval between two musical notes, the fundamental components of which have frequencies in the ratio two to one.

M.E., from O.Fr. otaves, from L. octava feminine of octavus, from → octa-, oct- + -avus adj. suffix.

Octâv, loan from Fr. as above.


Fr.: octet   

General: A group or series of eight.
Chemistry: A stable group of eight electrons which constitutes the outer electron shell of an atom of an inert gas (except helium whose only electron shell contains two electrons).

From → oct-, octa- + -et, as in duet.

Haštâyé, from haštâ "eightfold" + (y)é nuance suffix, as in dotâyé, → doublet.

haštâyi (#)

Fr.: octuple   

Eightfold; eight times as great.

L. octuplus, from octu- variant (before labials) of → oct- octa- + -plus "fold," from base of plicare "to fold, twist."

Haštâyi, from hašt "eight," → oct- octa- + -tâyi, from "fold, plait, ply; piece, part," also a multiplicative suffix; Mid.Pers. tâg "piece, part."


Fr.: octupôle   

A → multipole consisting of eight point charges. Octupole moments are much smaller than → quadrupole moments and very much smaller than → dipole moment.

oct-; → pole.

  چشمی، دیدگانی   
cašmi, didgâni

Fr.: oculaire   

1) Of, pertaining to, or for the eyes.
2) Optics: An alternative term for → eyepiece.

From L. ocularis "of the eyes," from oculus "eye," from PIE base *okw- "to see;" cf; Av. aši- "(both) eyes;" E. → eye.

Cašmi, related to cašm "eye" (Mid.Pers. cašm, Av. cašman- "eye," ākas- "to look," from prefix ā- + Proto-Iranian *kas- "to look, appear," cf. Skt. cáksus- "seeing"); didgâni, related to didgân "eyes," plural of didé "eye," 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").


Fr.: impair   

Of a number, not divisible by two.
A function such as f(x) with the property that f(-x) = - f(x) for any value of x; e.g. sin(x).

From M.E. odde, from O.N. oddi "odd (number)."

Tâq, related to tak "single, alone", from Mid.Pers. tak, tâg "single, alone," maybe related to tâi, tâ "unit, piece."

odd-even nucleus
  هسته‌ی ِ تاق-جفت   
haste-ye tâq-joft

Fr.: noyau impair-pair   

Nucleus which contains an odd number of protons and an even number of neutrons.

odd; → even; → nucleus.

odd-odd nucleus
  هسته‌ی ِ تاق-تاق   
haste-ye tâq-tâq

Fr.: noyau impair-impair   

Nucleus which contains an odd number of both protons and neutrons.

odd; → nucleus.


Fr.: oenologie   

The science of → wines. Same as enology.

From Gk. oeno-, from oinos cognate with → wine.

Bâdešenâsi, from bâdé, bâda "wine," from Mid.Pers. bâtak "wine," + -šenâsi, → -logy.

  ا ُرستد   
oersted (#)

Fr.: oersted   

The unit of magnitude of magnetic field strength or magnetic intensity in c.g.s. units, i.e. the force in dynes which a unit magnetic pole would experience at any point in a magnetic field.

In honor of Hans Christian Ørsted (1777-1851), the Danish physicist and philosopher, who was the first to notice the interaction of electric current and the magnetic needle (1819) thereby initiating the study of electromagnetism.

Of star
  ستاره‌ی ِ Of   
setâre-ye Of

Fr.: étoile Of   

An → O star whose spectrum displays strong N III 4634-4640-4642 emission and strong He II 4686 emission. The N III lines are always much stronger than C III 4647-4650-4651 when the latter are present. Historically, Of stars were considered to belong to the peculiar category, hence the f notation (see below). In his thesis work, Walborn (1971, ApJS 23, 257) removed them from that category and established them as the normal O-type → supergiants. He also used the notation ((f)), (f), and f to describe the progression from strong He II 4686 absorption, through weakened/absent, to emission, respectively, correlated with increasing N III emission strength, subsequently showing that it is a luminosity sequence -- the first such for stars earlier than O9.

The reason for the Of designation is that the letters Oa-Oe were used in the original Harvard classification to denote various types of → Wolf-Rayet and OB spectra. Therefore Of was the next available when Plaskett and Pearce (1931, Pub. Dominion Ap. Obs 5, 99) wished to distinguish O-type spectra with selective emission in N III 4634-4640-4642 and He II 4686 ("selective" because other lines from the same ions appear in absorption); → star.

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