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: 474
lock
  ۱) قفل؛ ۲) قفل کردن، ~ شدن   
1) qofl (#); 2) qofl kardan, ~ šodan

Fr.: 1) vérouille; 2) vérouiller, se vérouiller   

1) A device fitted to a gate, door, drawer, lid, etc, to keep it firmly closed and often to prevent access by unauthorized persons.
2) To fasten (a door, gate, etc) or (of a door, etc) to become fastened with a lock, bolt, etc, so as to prevent entry or exit (Dictionary.com).

M.E., from O.E. loc "fastening, bar;" cognate with M.L.G. lok, O.H.G. loh "dungeon," Ger. Loch "opening, hole," O.N. lok "a cover, lid;" akin to O.E. lucan "to shut."

Qofl, loan from Ar.

Lockman hole
  سوراخ ِ لاکمن   
surâx-e Lockman

Fr.: trou de Lockman   

A region in the sky lying roughly between the → pointer stars of the → Big Dipper that is almost free from → neutral hydrogen gas in the → Galaxy. It is centered at R.A. 10h 45m, Dec. +57° 20', has an area of 15 square degrees, and a → column density of NH I ≤ 5 x 1018 cm-2. The Lockman hole is one of the favorite directions for obtaining a clear and unobstructed view of objects in deep space, far beyond our own Galaxy.

Named after Felix J. Lockman et al., 1986, ApJ 302, 432; → hole.

locus
  محلگان   
mahalgân

Fr.: lieu géométrique   

The aggregate of all possible positions of a moving or generating element, e.g. the locus of points equidistant from a given point is a circle whose center is the given point.

From L. locus "place," from Old L. stlocus, literally "where something is placed," from PIE base *st(h)el- "to cause to stand, to place."

Mahalgân, from mahal "place, locality" + -gân relation and multiplicity suffix.

lodranite
  لودرانیت   
lodrânit

Fr.: lodranite   

A rare type of → achondritemeteorite.

Named after Lodhran (Punjab), Pakistan, where the type specimen fell on 1 October 1868.

LOFAR
     
LOFAR

Fr.: LOFAR   

A low frequency radio telescope network concentrated in the Netherlands with extensions into other European countries. It consists of a core and an extended → array in the Netherlands as well as in surrounding European countries with maximum → baselines of 2 km, 100 km, and 1,000 km respectively. LOFAR will be the largest radio telescope ever built, using a new concept based on a vast array of simple omni-directional antennas. The array will operate at the lowest frequencies that can be observed from Earth, at 30-250 MHz. About 75% of the construction is finished and LOFAR has already started its → commissioning period. When entirely finished, it will consist of 45,000 small antennas, distributed within 48 stations in the north east of the Netherlands, nearby parts of Germany, the UK, France, Sweden, and perhaps later Poland and Spain. The extensions in the United Kingdom, Germany, and France are completed. The French extension, located in the Nançay station of Paris Observatory (190 km south of Paris), is fully operational since December 2010. Moreover, a project to extend the low-frequency component of the Nançay station is under study. LOFAR is a forerunner of the future → Square Kilometer Array (SKA) project. See also the LOFAR homepage.

LOFAR, short for → LOw; → Frequency; → ARray.

logarithm
  لگاریتم   
logâritm (#)

Fr.: logarithme   

The → exponent of the → power to which it is necessary to raise a fixed number to produce the given number. The fixed number is called the → base. The logarithm of x to the base a, denoted loga(x), is the unique → real number  y such that ay = x. In the familiar system of → common logarithms, the base is 10. In the system of → natural logarithms, the base is e = 2.7182818 ... (→ number e). For example, the logarithm of 100 (base 10) is 2 because 102 = 100.

Mod.L. logarithmus, coined by Scottish mathematician John Napier (1550-1617), literally "ratio-number," from Gk. logos "proportion, ratio, word," → logic + arithmos "number," → arithmetic.

logarithmic
  لگاریتمی   
logâritmi (#)

Fr.: logarithmique   

Of or pertaining to a → logarithm.

logarithm; → -ic.

logarithmic extinction
  خاموشی ِ لگاریتمی   
xâmuši-ye logâritmi

Fr.: extinction logarithmique   

Same as → reddening coefficient.

logarithmic; → extinction.

logarithmic scale
  مرپل ِ لگاریتمی   
marpel-e logâritmi

Fr.: échelle logarithmique   

A scale of measurement in which an increase of one unit represents a tenfold increase in the quantity measured (for common logarithms)

logarithmic; → scale.

logic
  گوییک، چمگوییک   
guyik, cemguyik (#)

Fr.: logique   

1) The science that investigates the principles governing correct or reliable inference.
2) The system or principles of reasoning applicable to any branch of knowledge or study.
3) A particular method of reasoning or argumentation.

M.E. logik; O.Fr. logique, from L. (ars) logica, from Gk. logike (techne) "reasoning (art)," from feminine of logikos "pertaining to speaking or reasoning," from logos "reason, idea, word."

Guyik, from guy- present stem of goftan "to say, speak, relate, tell; to compose a poem," from Mid.Pers. guftan "to say, tell, utter;" O.Pers. gaub- "to say" + -ik, → -ic.
Cemguyik, from Mid.Pers. cimgôwâgih "logic," from cim "cause, reason, meaning" (Proto-Iranian *cahmāt "what for;" cf. Skt. kasmāt "why, where from," kim "what") + gôwâgih Mod.Pers. guyi, as above.

logic diagram
  نمودار ِ گوییکی   
nemudâr-e guyiki

Fr.: diagramme logique   

A diagram that uses special symbols called logic symbols to represent the detailed functioning of electronic logic circuits. The symbols do not represent the type of electronics used, but only their functions.

logic; → diagram.

logical
  گوییک، گوییکی، گوییکوار   
guyik, gyuiki, guyikvâr

Fr.: logique   

1) According to or agreeing with the principles of logic.
2) Reasoning in accordance with the principles of logic, as a person or the mind.
3) Of or pertaining to logic (Dictionary.com).

logic; → -al.

logical connective
  هابندار ِ گوییکی   
hâbandâr-e guyiki

Fr.: connecteur logique   

A symbol that can be combined with one or more → sentences in order to form a new sentence. For example "and" (∧), "or" (∨) "not" (¬), "if-then" (→), and "iff" (⇔).

logical; → connective.

logically equivalent
  گوییکانه هموگ‌ارز   
guyikâné hamug-arz

Fr.: logiquement équivalent   

Describing two → compound propositions → if and only if they have the same → truth table.

logical; → equivalent.

lognormal distribution
  واباژش ِ لگاریتمی-هنجارور   
vâbâžeš-e logâritmi-hanjârvar

Fr.: distribution logarithmico-normale   

A → probability distribution in which the natural logarithm (logX) of the → random variable (X) has a → Gaussian distribution.

logarithm; → normal distribution.

Lomb-Scargle periodogram
  دوره‌نگاشت ِ لومب-اسکارگل   
dowrenegâšt-e Lomb-Scargle

Fr.: périodogramme de Lomb-Scargle   

An algorithm for detecting and characterizing periodic signals in unevenly-sampled data. The Lomb-Scargle periodogram has a particularly wide use within the astronomy community. This method allows efficient computation of a Fourier-like → power spectrum estimator from such unevenly-sampled data, resulting in an intuitive means of determining the period of oscillation (see VanderPlas, 2017, astro-ph/1703.09824 and references therein).

Named after Lomb, N. R. 1976, Ap&SS 39, 447 and Scargle, J. D. 1982, ApJ 263, 835; → periodogram.

long
  دراز   
derâz (#)

Fr.: long   

1) Having considerable linear extent in space. → very-long-baseline interferometry (VLBI).
2) Having considerable duration in time. → long-period variable.

M.E. longe, O.E. lang, long, akin to O.H.G., Ger. lang "long," O.N. langr, M.Du. lanc, Goth. laggs "long," L. longus, → longitude.

Derâz "long," Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time)."

long-period comet
  دمدار ِ درازدوره   
domdâr-e derâz dowré

Fr.: comète à longue période   

A comet with orbital period of more than 200 years. → short-period comet; → periodic comet.

long; → period; → comet.

long-period variable
  ورتنده‌ی ِ درازدوره   
vartande-ye derâz dowré

Fr.: variable à longue période   

A type of → variable star in which variations in brightness occur over long time-scales of months or years. The term generally refers to → Mira variable types.

long; → period; → variable.

longitude
  درژنا   
derežnâ

Fr.: longitude   

The angular distance on the Earth's surface, measured east or west from the prime meridian at Greenwich to the meridian passing through a position, expressed in degrees (or hours), minutes, and seconds.

L. longitudo "length," from longus "long," cognate with Pers. derâz, as below, Gk. dolikhos "elongated;" O.H.G., Ger. lang, O.N. langr, M.Du. lanc, Goth. laggs "long;" PIE base *dlonghos- "long."

Derežnâ, from derež (Kurdi, Laki), variants darg "length; long, tall" (Zâzâ), darγ (Ossetic), derâz "long" + -nâ noun forming suffix from adjective, as in derâznâ, pah(n)nâ, farâxnâ, tangnâ, tiznâ. The first element from Mid.Pers. drâz "long;" O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "lon (in space and time);" PIE *dlonghos- "long," as above.

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