An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) A curved structure, normally in the vertical plane, that spans an opening.
2) Any overhead curvature resembling an arch. → Arches cluster.

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.

Any of the four vaulted structures in the foot: the internal (medial) longitudinal, the outer (lateral) longitudinal, and two transverse (Medical Dictionary, Farlex).

→ arch; → foot.

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.

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.

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).

→ arche-; → type.

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.
2) Computers: The arrangement of the various devices in a computer system or network. See also → software architecture.

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.

Put in modern notation, if α and β are acute angles and if β <α, then sin α / sin β <α / β < tan α / tan β. Aristarchus probably used this inequality to show that the Sun is between 18 and 20 times as far from the Earth as the Moon is.

Aristarchus of Samos (c.310-c.230 BC); → inequality.

Same as → archaeoastronomy, megalithic astronomy.

Any extensive record or collection of data, observational (usually obtained with a particular instrument) or theoretical (grid of models usually regarding a particular branch of astrophysics).

→ data; → archive.

Of, belonging to, or characteristic of a hierarchy. → hierarchical clustering; → hierarchical cosmology; → hierarchical multiple system; → hierarchical structure formation.

→ hierarchy; → -al.

A model in which a system of self-gravitating particles will gradually aggregate into larger and larger gravitationally bound groups and clusters.

→ hierarchical; → clustering.

A cosmology characterized by clustering of galaxy clusters in increasingly larger systems.

→ hierarchical; → cosmology.

A → multiple star system in which the stars can be divided into two groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Hierarchical multiple systems have long-term dynamical stability.

→ hierarchical; → multiple; → system.

A cosmological → structure formation model in which the smallest gravitationally bound structures (→ quasars and galaxies) form first, followed by → groups, → galaxy clusters, and → superclusters of galaxies.

→ hierarchical; → structure; → formation.

A triple star system in which the (inner) binary is orbited by a third body in a much wider orbit. → hierarchical multiple system.

→ hierarchical; → stellar; → system.

A system in which the components are organized in increasingly larger structures.

From O.Fr. ierarchie, from M.L. hierarchia "ranked division of angels," from Gk. hierarchia "rule of a high priest," from hierarches "high priest, leader of sacred rites," from ta hiera "the sacred rites" (neut. pl. of hieros "sacred") + archein "to lead, rule."

Pâygân, from pâyé "step, rank, degree," from pây, pâ "foot, step," from Mid.Pers. pâd, pây; Av. pad- "foot" (cf. Skt. pat; Gk. pos, gen. podos; L. pes, gen. pedis; P.Gmc. *fot; E. foot; Ger. Fuss; Fr. pied; PIE *pod-/*ped-) + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna, from Proto-Iranian *kāna-ka-.

A high-precision echelle spectrograph built for exoplanet findings and installed on the ESO's 3.6m telescope at La Silla Observatory in Chile. The first light was achieved in February 2003. HARPS has discovered dozens of exoplanets, making it the most successful planet finder behind the Kepler space observatory. HARPS can detect movements as small as 0.97 m s^-1 (3.5 km h^-1), with an effective precision of the order of 30 cm s^-1, and a → resolving power of 120,000 (Mayor et al., 2003, ESO Messengar 114, 20).

→ high; → accuracy; → radial; → velocity; → planet; → search; → -er.