late 14c., "the seven virtues personified;" early 15c., "the Pleiades" (see Pleiades), seven daughters of Atlas and Pleione, placed among the stars by Zeus and popularly known as the Seven Stars (see seven).
In late 20c. applied to seven venerable and prestigious U.S. colleges for women only: Barnard, Bryn Mawr, Mount Holyoke, Radcliffe, Smith, Vassar, and Wellesley. The phrase also was applied to seven similar cannon used by the Scots at Flodden. As a late-20c. name for the major multi-national petroleum companies, Seven Sisters is attested from 1962. They were listed in 1976 as Exxon, Mobil, Gulf, Standard Oil of California, Texaco, British Petroleum, and Royal Dutch Shell.
"smooth, lustrous silken cloth; silk fabric with a very glossy surface and the back less so," mid-14c., from Old French satin (14c.), perhaps from Arabic (atlas) zaytuni, literally "(satin) from Zaitun," name of a place in China, perhaps modern Quanzhou in Fukien province, a major port in the Middle Ages with a resident community of European traders.
On this theory the form of the word was influenced in French by Latin seta "silk." OED finds the Arabic connection etymologically untenable and takes the French word as being from Latin seta via a Late Latin or Vulgar Latin *pannus setinus "silken cloth."
As an adjective from mid-15c., "made of silk." By c. 1600 as "clothed in satin;" by 1826 as "resembling satin."
Cognates include Greek talantos "bearing, suffering," tolman "to carry, bear," telamon "broad strap for bearing something," talenton "a balance, pair of scales," Atlas "the 'Bearer' of Heaven;" Lithuanian tiltas "bridge;" Sanskrit tula "balance," tulayati "lifts up, weighs;" Latin tolerare "to bear, support," perhaps also latus "borne;" Old English þolian "to endure;" Armenian tolum "I allow." Figurative sense of "praise highly" in English is first attested c. 1500. Related: Extolled; extolling.
late 14c., Pliades, "visible open star cluster in the constellation Taurus," in Greek mythology they represent the seven daughters of Atlas and Pleione, transformed by Zeus into seven stars. From Latin Pleiades, from Greek Pleiades (singular Plēias), 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. The star cluster is 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.