ploughyoudaoicibaDictYouDict[plough 词源字典]
plough: [OE] Plough was not the original English word for an ‘implement for turning over the soil’. That was Old English sulh, a relative of Latin sulcus ‘furrow’. Plough was borrowed in the 10th century from Old Norse plógr, a descendant of prehistoric Germanic *plōgaz. And this in turn was derived from a base *plōgacquired from one of the ancient Indo-European languages of northern Italy (source also of Latin plaustrum ‘wagon’). The earliest record we have of the word being used for the characteristically shaped group of seven stars in Ursa major is from early 16th-century Scotland.
[plough etymology, plough origin, 英语词源]
ArcturusyoudaoicibaDictYouDict
late 14c., bright star in the constellation Bootes (also used of the whole constellation), from Latin Arcturus, from Greek Arktouros; anciently associated with the Bear, and its name is Greek for "guardian of the bear." See arctic; second element is from ouros "watcher, guardian, ward," from PIE root *wer- (4) "perceive" (see ward (n.)).

Arcturus in the Bible (Job ix:9 and xxxviii:32) is a mistranslation by Jerome (continued in KJV) of Hebrew 'Ayish, which refers to what we see as the "bowl" of the Big Dipper. In Israel and Arabia, the seven stars of the Great Bear seem to have been a bier (the "bowl") followed by three mourners. In the Septuagint it was translated as Pleiada, which is equally incorrect. The double nature of the great bear/wagon (see Big Dipper) has given two different names to the constellation that follows it: Arktouros "bear-ward" and bootes "the wagoner."
Charles's Wain (n.)youdaoicibaDictYouDict
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 (19c., chiefly American).

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 the "unlearned" 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 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.
Pleiades (n.)youdaoicibaDictYouDict
late 14c., the seven daughters of Atlas and Pleione, transformed by Zeus into seven stars, from Latin Pleiades, from Greek Pleiades, perhaps literally "constellation of the doves" from a shortened form of peleiades, plural of peleias "dove" (from PIE root *pel- "dark-colored, gray"). Or perhaps from plein "to sail," because the season of navigation begins with their heliacal rising.

Old English had the name from Latin as Pliade. Mentioned by Hesiod (pre-700 B.C.E.), only six now are visible to most people; on a clear night a good eye can see nine (in 1579, well before the invention of the telescope, the German astronomer Michael Moestlin (1550-1631) correctly drew 11 Pleiades stars); telescopes reveal at least 500. Hence French pleiade, used for a meeting or grouping of seven persons.
septentrion (n.)youdaoicibaDictYouDict
"the Big Dipper;" Middle English septentrioun (1530s in reference to the star pattern; late 14c. as "the North," and septentrional "northern," in reference to the sky, is attested from late 14c.), from Latin septentriones, septemtriones (plural) "the Great Bear, the seven stars of the Big Dipper;" also figuratively "the northern regions, the North;" literally "seven plow oxen," from septem "seven" (see seven) + trio (genitive triones) "plow ox," from stem of terere (past participle tritus) "to rub" (see throw (v.)). Also see Charles's Wain.
seven (n.)youdaoicibaDictYouDict
Old English seofon, from Proto-Germanic *sebun (cognates: Old Saxon sibun, Old Norse sjau, Swedish sju, Danish syv, Old Frisian sowen, siugun, Middle Dutch seven, Dutch zeven, Old High German sibun, German sieben, Gothic sibun), from PIE *septm "seven" (cognates: Sanskrit sapta, Avestan hapta, Hittite shipta, Greek hepta, Latin septem, Old Church Slavonic sedmi, Lithuanian septyni, Old Irish secht, Welsh saith).

Long regarded as a number of perfection (seven wonders; seven sleepers, the latter translating Latin septem dormientes; seven against Thebes, etc.), but that notion is late in Old English and in German a nasty, troublesome woman could be eine böse Sieben "an evil seven" (1662).

Magical power or healing skill associated since 16c. with the seventh son ["The seuenth Male Chyld by iust order (neuer a Gyrle or Wench being borne betweene)," Thomas Lupton, "A Thousand Notable Things," 1579]. The typical number for "very great, strong," as in seven-league boots in the fairy story of Hop o'my Thumb. The Seven Years' War (1756-63) is also the Third Silesian War.

The Seven Stars (Old English sibunsterri), usually refers to the Pleiades, though in 15c. and after this name occasionally was given to the Big Dipper (which also has seven stars), or the seven planets of classical astronomy. Popular as a tavern sign, it might also (with six in a circle, one in the center) be a Masonic symbol.
FOOL: ... The reason why the
seven stars are no more than seven is a pretty reason.
LEAR: Because they are not eight?
FOOL: Yes, indeed: thou wouldst make a good fool.
["King Lear," I.v.]
Seven SistersyoudaoicibaDictYouDict
"the Pleiades," early 15c. (see Pleiades), seven daughters of Atlas and Pleione, placed among the stars by Zeus. The Pleiades also are known as the Seven Stars (see seven). As a late-20c. name for the major multi-national petroleum companies, it is attested from 1962. They were listed in 1976 as Exxon, Mobil, Gulf, Standard Oil of California, Texaco, British Petroleum, and Royal Dutch Shell.