arc of separation
Fr.: arc de séparation
arc of vision
Fr.: arc de vision
kamân-sâniyé, sâniye-ye kamâni
Fr.: seconde de degré
A unit of angular size equal to 1/3.600 of a degree.
Fr.: spectre d'étincelle
The spectrum produced by an atom or mixture of atoms as a result of vaporization within an electric arc generated between two electrodes.
1) A curved structure, normally in the vertical plane, that spans an opening.
M.E. arch(e), from O.Fr. arche "arch of a bridge," from L. arcus "a bow," → arc.
Taq "arch," from tâk, contraction of târak, → vertex.
The study that deals with the astronomical knowledge of prehistoric peoples (season events, calendars, observing sites, astronomical alignments) and its influence on their cultures and societies (mythologies, religions, life). Archaeoastronomy covers the intersection between astronomy and archaeology. Same as → astroarchaeology, megalithic astronomy.
Archeoastronomy, from L. archaeo-, archeo "ancient; earlier; primitive," from Gk. arkhaio-, from arkhaios "ancient" + → astronomy.
Bâstânaxtaršenâsi, from bâstân "ancient" + axtaršenâsi, → astronomy.
Fr.: arché-, archi
A prefix meaning "principal, prior, original, first, early" Same as archi-. → archetype.
From Gk. arkhe-, from arckhon "ruler," noun use of p.p. of arkhein "to rule."
Sar-, from sar "top, summit, the capital of a pillar," → head.
Fr.: amas des Arches
One of the three → Galactic center clusters supposed to be the densest young → massive star cluster in the Milky Way. It contains the richest collection of → O stars and → WN Wolf-Rayet stars in any cluster in the Galaxy, thus representing the largest collection of the most massive stars in the Galaxy. With its estimated age of 2-3 million years, the Arches cluster is the youngest of the massive clusters in the Galactic center. → Quintuplet cluster; → Central cluster (Figer et al. 2002, ApJ 581, 258; and 1999, ApJ 525, 750).
Arches, from the presence of Galactic center thermal → arched filaments, about 100 → light-years in projection from the Galactic center (Morris & Yusef-Zadeh, 1985, AJ 90, 2511), from M.E. arche, O.Fr. arche "arch of a bridge," from L. arcus, → arc; → cluster.
The original pattern or model from which all things of the same kind are copied or on which they are based; a model or first form; prototype (Dictionary.com).
Fr.: principe d'Archimède
A body immersed totally or partially in a liquid is buoyed up by a force equal to the weight of the liquid displaced by the body. → buoyancy.
Archimedes of Syracuse (c. 287 BC - c. 212 BC), Greek mathematician and inventor; → principle.
Arašmidos altered form of Archimedes in classical Ar. texts; parvaz, → principle.
1) The art or practice of designing and building structures.
M.E., from M.Fr. architecture, from L. architectura, from architectus "architect," from Gk. arkhitekton "master builder, director of works," from arkhi- "chief" + tekton "builder, carpenter," → technique.
Mehrâzik, from mehrâz literally "chief mason," from meh- "great, large," → high, + râz "mason, builder" (Borhân-e Qâte'), from Mid.Pers. râz "builder, architect," probably related to O.Pers. râs-, Av. râz- "to direct, set, put in line" (with many cognates in Pers., such as râst "straight, direct, true;" raj, rak, râk, rezg (Lori), radé, râdé "line, rule, row," rasté, râsté "row, a market with regular ranges of shops;" ris, risé "straight"); cf. Skt. raj- "to direct, stretch," rjuyant- "walking straight;" Gk. orektos "stretched out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" Ger. recht; E. right; PIE base *reg- "move in a straight line," hence, "to direct, rule;" + -ik, → -ics.
Any extensive record or collection of data.
Archive, from Fr. archives, from L. archivum, from Gk. arkheion "government house, town hall," from arkhe "government," from arkhein "to rule".
Bâygâni, maybe from *pâygâni, from pây-, pâyidan "to watch, guard, take care, conserve" + -gân, suffix referring to group, collection, + -i, noun-forming suffix.
Hudargân, šomâlgân (#)
The north polar area, north of latitude 66° 33' 8'' N.
Arctic, from O.Fr. artique, from L. arcticus, from Gk. arktikos "of the north," literally "of the (northerly prominent constellation) Bear," from arktos "bear" (cf. Av. arša-, Mod.Pers. xers, Tabari aš, Skt. rksa, L. ursus; PIE *rtko-).
Hudargân, from hudar, → north,
+ -gân prefix denoting the direction.
Arcturus (α Boötis)
Xersbân, Semâk-e râmeh (#)
The fourth brightest star in the sky (V magnitude -0.06) lying in the constellation → Boötes at a distance of about 35 light-years. Arcturus is a red giant of spectral type K2 IIIp.
L. Arcturus, from Gk. Arktouros "guardian of the bear," arktos "bear," → Arctic + ouros "guardian, watcher".
Xersbân "guardian of the bear," from xers "bear" (Mid.Pers.
xirs, Av. arša-, cognate with Gk. arktos,
Skt. rksa, L. ursus; PIE *rtko-) +
-bân suffix meaning "watcher, keeper, guard".
A particular extent of space or surface; the scope of a concept, operation, or activity.
The etymology is not clear; perhaps akin to L. arere "to be dry" → arid.
Pahné "area, field," from pahn "broad, wide" (Mid.Pers. pah(a)n, Av. pathana- "broad, wide, spacious," probably related to perethav- "broad, wide," Skt. prthav-, Gk. platus; PIE *plat- "to spread") + noun forming suffix -é.
The study of the surface features of Mars; the geography of Mars.
Areography, from Gk. Ares "Mars" + → -graphy.
Bahrâm-negâri, from Bahrâm "Mars" + -negâri→ -graphy.
The study of the origin, history, and structure of Mars; the geology of Mars.
Areology, from Gk. Ares "Mars" + → -logy.
Bahrâm-šenâsi, from Bahrâm "Mars" + -šenâsi→ -logy.
Fr.: diagramme d'Argand
A geometrical representation of → complex numbers, which like the → Cartesian coordinates, uses two reference perpendicular axes. The horizontal axis represents the → real number part of the number and the perpendicular axis the → imaginary number part.
Named after Jean Robert Argand (1768-1822), a Swiss mathematician, who introduced this representation; → diagram.
Fr.: méthode d'Argelander
Friedrich Wilhelm Argelander (1799-1875), German astronomer. His most important work was his compilation of the Bonner Durchmusterung; → method.
Argo (Argo Navis; Ship Argo)
Fr.: Navire Argo
The ship in which Jason sailed in search of the Golden Fleece.
Kašti "ship," from Mid.Pers. kaštik.