Etymology
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primum mobile (n.)

"the first source of motion," mid-15c., from Medieval Latin (11c.), literally "the first movable thing;" see prime (adj.) + mobile.

In the Ptolemaic system of astronomy, the tenth or outermost of the revolving spheres of the universe, which was supposed to revolve from east to west in twenty-four hours, and to carry the others along with it in its motion; hence, any great or first source of motion. [Century Dictionary]

A translation of Arabic al-muharrik al-awwal "the first moving" (Avicenna). Englished by Chaucer as the firste Moeuyng (c. 1400). Old science also had primum frigidum "pure cold: an elementary substance, according to the doctrine of Parmenides."


 

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Ophiuchus 

ancient constellation (representing Aesculapius), 1650s, from Latin, from Greek ophioukhos, literally "holding a serpent," from ophis "serpent" (see ophio-) + stem of ekhein "to hold, have, keep" (from PIE root *segh- "to hold").

Translated in Latin as Anguitenens and Serpentarius. Milton's "Ophiuchus huge in th' Arctick Sky" ("Paradise Lost") is a rare (minor) lapse for a poet who generally knew his astronomy; the constellation actually straddles the celestial equator, and, as its modern boundaries are drawn, dips into the zodiac: The sun passes through Ophiuchus from about Nov. 30 to Dec. 18. The serpent now is treated as a separate constellation.

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perpendicular (adj.)

late 15c., perpendiculer, of a line, "lying at right angles to the horizon" (in astronomy, navigation, etc.), from an earlier adverb (late 14c.), "at right angles to the horizon," from Old French perpendiculer, from Late Latin perpendicularis "vertical, as a plumb line," from Latin perpendiculum "plumb line," from perpendere "balance carefully," from per "thoroughly" (see per) + pendere "to hang, cause to hang; weigh" (from PIE root *(s)pen- "to draw, stretch, spin").

The meaning "perfectly vertical" is by 1590s. As a noun, "a line that meets another line or plane at right angles," from 1570s. The earlier noun was perpendicle (c. 1400). Related: Perpendicularly; perpendicularity.

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zone (n.)

late 14c., from Latin zona "geographical belt, celestial zone," from Greek zōnē "a belt, the girdle worn by women at the hips," from zōnnynai "to gird," from PIE root *yos- "to gird" (source also of Avestan yasta- "girt," Lithuanian juosiu, juosti "to gird," Old Church Slavonic po-jasu "girdle"). The 10c. Anglo-Saxon treatise on astronomy translates Latin quinque zonas as fyf gyrdlas.

Originally one of the five great divisions of the earth's surface (torrid, temperate, frigid; separated by tropics of Cancer and Capricorn and Arctic and Antarctic circles); meaning "any discrete region" is first recorded 1822. Zone defense in team sports is recorded from 1927.

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alpha (n.)
c. 1300, from Latin alpha, from Greek alpha, from Hebrew or Phoenician aleph (see aleph). The Greeks added -a because Greek words cannot end in most consonants. Sense of "beginning of anything" is from late 14c., often paired with omega (the last letter in the Greek alphabet, representing "the end"); sense of "first in a sequence" is from 1620s. In astronomy, the designation of the brightest star of each constellation (the use of Greek letters in star names began with Bayer's atlas in 1603). Alpha male was in use by c. 1960 among scientists studying animals; applied to humans in society from c. 1992.
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parapsychology (n.)

"the study of phenomena outside the sphere of orthodox psychology," by 1923, from German para-psychologie; see para- (1) "beside" + psychology. Related: Parapsychological.

Similarly, [Prof. Hans Driesch] includes under "parapsychology" such phenomena as telepathy and clairvoyance, which he regards as mere extensions from ordinary mental phenomena, rather than as fundamentally different processes. He believes that the same orderly process by which unclassified and diverse processes have been systematized,—alchemy becoming chemistry, astrology becoming astronomy,—is at work now,—to make, in place of the mysterious tradition of Occultism, a science which will really be an extension from scientific psychology and biology. ["Journal of the American Society for Psychical Research," April 1923]
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Io 

in Greek mythology, daughter of the river god Inachus, she was pursued by Zeus, who changed her to a heifer in a bid to escape the notice of Juno, but she was tormented by a gadfly sent by Juno.

The Jovian moon was discovered in 1610; the mythological names for all of them (objects of Jupiter's seductions in the myths) were proposed shortly thereafter but not widely used before mid-19c. (Compare Titan).

These bodies [the Jovian moons] have been called in the order of their distance from Jupiter, Hebe, Ganymede, Themis, and, Metis — these names are, however, little used at present, and they are distinguished by the order of their distance from Jupiter, the first being the nearest. [Dionysius Lardner and M. Argo, "Popular Lectures on Astronomy," New York, 1845]
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-id 
adjectival word-forming element, especially in zoology, "belonging to, connected with, member of a group or class," in some cases probably via from French -ide, back-formed from Modern Latin names of zoological classes in -idae, as arachnid "a spider" from the biological class name arachnidae.

This -idae is the plural of Latin -ides, a masculine patronymic (indicating "descent from"), from Greek -ides "son of," denoting descent from the person to whose name it is attached (such as Heraklides).

In astronomy, of meteor showers, "having its radiant in" the constellation named (Perseid, Leonid, etc.), it probably represents Latin -idis, from Greek -idos, the genitive of the feminine form of the patronymic suffix.
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apparent (adj.)
late 14c., "indisputable, clearly understood;" c. 1400, "easily seen or perceived," from Old French aparant "evident, obvious, visible," from Latin apparentem (nominative apparens) "visible, manifest," present participle of apparere "appear, come in sight" (see appear).

First attested in phrases such as heir apparent (see heir). Meaning "superficial, spurious" is from c. 1400; that of "appearing to the senses or mind but not necessarily real" is from 1640s. Apparent magnitude in astronomy (how bright a heavenly body looks from earth, as opposed to absolute magnitude, which is how bright it really is) is attested from 1875. Middle English had noun forms apparence, apparency, but both are obsolete from 17c.
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Charles's Wain (n.)

Old English Carles wægn, a star-group associated in medieval times with Charlemagne, but originally with the nearby bright star Arcturus, which is linked by folk etymology to Latin Arturus "Arthur." Which places the seven-star asterism at the crux of the legendary association (or confusion) of Arthur and Charlemagne. Evidence from Dutch (cited in Grimm, "Teutonic Mythology") suggests that it might originally have been Woden's wagon. More recent names for it are the Plough (by 15c., chiefly British) and the Dipper (1833, chiefly American).

It is called "the Wagon" in a Mesopotamian text from 1700 B.C.E., and it is mentioned in the Biblical Book of Job. The seven bright stars in the modern constellation Ursa Major have borne a dual identity in Western history at least since Homer's time, being seen as both a wagon and a bear: as in Latin plaustrum "freight-wagon, ox cart" and arctos "bear," both used of the seven-star pattern, as were equivalent Greek amaxa (Attic hamaxa) and arktos.

The identification with a wagon is easy to see, with four stars as the body and three as the pole. The identification with a bear is more difficult, as the figure has a tail longer than its body. As Allen writes, "The conformation of the seven stars in no way resembles the animal,--indeed the contrary ...." But he suggests the identification "may have arisen from Aristotle's idea that its prototype was the only creature that dared invade the frozen north." The seven stars never were below the horizon in the latitude of the Mediterranean in Homeric and classical times (though not today, due to precession of the equinoxes). See also arctic for the identification of the bear and the north in classical times.

A variety of French and English sources from the early colonial period independently note that many native North American tribes in the northeast had long seen the seven-star group as a bear tracked by three hunters (or a hunter and his two dogs).

Among the Teutonic peoples, it seems to have been only a wagon, not a bear. A 10c. Anglo-Saxon astronomy manual uses the Greek-derived Aretos, but mentions that "unlearned men" call it "Charles's Wain":

Arheton hatte an tungol on norð dæle, se haefð seofon steorran, & is for ði oþrum naman ge-hatan septemtrio, þone hatað læwede meon carles-wæn. ["Anglo-Saxon Manual of Astronomy"] 

[Septemtrio, the seven oxen, was yet another Roman name.] The star picture was not surely identified as a bear in English before late 14c.

The unlearned of today are corrected that the seven stars are not the Great Bear but form only a part of that large constellation. But those who applied the name "Bear" apparently did so originally only to these seven stars, and from Homer's time down to Thales, "the Bear" meant just the seven stars. From Rome to Anglo-Saxon England to Arabia to India, ancient astronomy texts mention a supposed duplicate constellation to the northern bear in the Southern Hemisphere, never visible from the north. This perhaps is based on sailors' tales of the Southern Cross.

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