Online Etymology Dictionary

separationist (n.): 1831, from separation + -ist.
separatism (n.): 1620s, from separate + -ism. First used in a denominational religious sense; from 1866 in a political sense.
separatist: c. 1600, from separate + -ist. First used in a denominational religious sense; of political separations from 1871.
separator (n.): c. 1600, "separatist," agent noun from separate (v.). As a mechanical device for separating, from 1831.
separatrix (n.): line or hooked line used to separate printed figures, originally with numerals and used where modern texts use a decimal point, also in other specialized senses, from Late Latin (linea) separatrix, feminine agent noun from separare (see separate (v.)).
Sephardim: plural of Sephardi "a Spanish or Portuguese Jew" (1851), from Modern Hebrew Sepharaddim "Spaniards, Jews of Spain," from Sepharad, name of a country mentioned only in Obad. v:20, probably meaning "Asia Minor" or a part of it (Lydia, Phrygia), but identified by the rabbis after the Jonathan Targum as "Spain." Related: Sephardic.
sepia (n.): "rich brown pigment," 1821, from Italian seppia "cuttlefish" (borrowed with that meaning in English by 1560s), from Latin sepia "cuttlefish," from Greek sepia "cuttlefish," related to sepein "to make rotten" (see sepsis). The color was that of brown paint or ink prepared from the fluid secretions of the cuttlefish. Meaning "a sepia drawing" is recorded from 1863.
sepoy (n.): "native of India in British military service," 1717, from Portuguese sipae, from Urdu sipahi, from Persian sipahi "soldier, horseman," from sipah "army." The Sepoy Mutiny was 1857-8.
sepsis (n.): 1876, "putrefaction," from Modern Latin sepsis, from Greek sepsis "putrefaction," from sepein "to rot," of unknown origin.
sept (n.): 1540s, "enclosed area," from Latin septum (see septum). As "division of a nation or tribe," 1510s, "prob. a var. of sect" [OED].
sept-: see septi-.
septangle (n.): 1550s, from Late Latin septangulus, from Latin sept- "seven" (see septi-) + angulus "angle" (see angle (n.)). Related: Septangular.
septem-: word-forming element meaning "seven," from Latin septem-, from septem "seven" (see seven).
September: late Old English, from Latin September (also source of Old French Septembre, Spanish Setiembre, Italian Settembre, German September), from septem "seven" (see seven). So called because it was the seventh month of the old Roman calendar, which began the year in March; Julian calendar reform (46 B.C.E.) shifted the new year back two months. For -ber suffix, see December. Replaced Old English hærfestmonað, haligmonað. Related: Septembral.
Septembrist (n.): 1798 in reference to French history, a participant in the massacre of the political prisoners in Paris, Sept. 2-5, 1792. In French, Septembriseur, hence English Septembriser (1797). Hence also septembrize "assassinate while in custody" (1793).
septemdecimal (adj.): "of seventeen years," in reference to cicadas, 1885, from Latin septemdecim "seventeen" ((see seven, ten) + -al (1). Related: Septemdecimally.
septentrion (n.): "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.
septet (n.): 1828, from German Septett, from Latin septem "seven" (see seven).
septi-: before vowels sept-, word-forming element meaning "seven," from Latin septem (see seven).
septic (adj.): c. 1600, from Latin septicus "of or pertaining to putrefaction," from Greek septikos "characterized by putrefaction," from sepein "make rotten or putrid, cause to rot" (see sepsis). Septic tank is attested from 1902.
septicemia (n.): 1857, Modern Latin septicæmia, from French septicoemi, coined irregularly by French physician Pierre-Adolphe Piorry (1794-1879) in 1837 from Greek septikos (see septic) + haima "blood" (see -emia).
Dr. Piorry, in a second communication, insists upon the fact, that in a great number of cases the decaying contents of the uterus, and the putrid infection of the blood from this source, constitute the so-called puerperal fever, and he thinks that the discussion in the Academy is only a fight about words, as the different speakers agree, without knowing it themselves, upon the nature of the disease. He proposes the name of septicemia, as best designating the sources of the disease, viz., from putrid infection from the uterus, and by the respiration of an atmosphere pregnant with septic particles. ... The admission of this septicemia explains the putrid accidents, as observed in men, the foetus, and wounded persons during a puerperal epidemic. [E. Noeggerath and A. Jacobi, "Contributions to Midwifery," New York, 1859]
septillion (n.): 1680s, from sept- (see septi-) + (m)illion. Compare billion.
septuagenarian (adj.): "of age 70, seventy-year-old," 1793, from Latin septuagenarius "containing seventy," from septuageni "seventy each," related to septuaginta "seventy" (see Septuagint). Noun meaning "a 70-year-old person" first recorded 1805. As an adjective, septuagenary is recorded from c. 1600.
Septuagint (n.): "Greek version of the Old Testament," 1630s, earlier as the word for the translators collectively (1570s), from Late Latin septuaginta (interpretes) "seventy (interpreters)," from Latin septuaginta "seventy," from septem "seven" (see seven) + -ginta "tens, ten times," from PIE *dkm-ta-, from *dekm- "ten" (see ten).

So called in reference to the (incorrect) tradition that the translation was done 3c. B.C.E. by 70 or 72 Jewish scholars (in Middle English, the Seuenty turneres) from Palestine and completed in 70 or 72 days. The translation is believed now to have been carried out at different times by an undetermined number of Egyptian Jews. Often denoted by Roman numerals, LXX. Related: Septuagintal.
septum (n.): "partition between the nostrils," 1690s, Modern Latin, from Latin saeptum "a fence, enclosure, partition," from neuter past participle of saepire "to hedge in," from saepes "hedge, fence." Related: Septal.
sepulchral (adj.): 1610s, "pertaining to a burial or place of burial," from Latin sepulcralis "of a tomb, sepulchral," from sepulcrum (see sepulchre) + -al (1). Transferred sense of "gloomy" is from 1711. Related: Sepulchrally.
sepulchre (n.): also sepulcher, c. 1200, "tomb, burial place," especially the cave where Jesus was buried outside Jerusalem (Holy Sepulcher or Saint Sepulcher), from Old French sepulcre "tomb; the Holy Sepulchre" (11c.), from Latin sepulcrum "grave, tomb, place where a corpse is buried," from root of sepelire "to bury, embalm," originally "to perform rituals on a corpse," from PIE *sep-el-yo-, suffixed form of root *sep- (2) "to handle (skillfully), to hold (reverently);" source also of Sanskrit saparyati "honors." No reason for the -ch- spelling, which dates to 13c. Whited sepulchre "hypocrite" is from Matt. xxiii.27.
sepulture (n.): "burial, interment," late 13c., from Old French sepulture, sepoutre "tomb, coffin" (12c.), from Latin sepultura "burial, funeral obsequies," from sepult-, past participle stem of sepelire "to bury" (see sepulchre).
sequacious (adj.): "given to following leaders," 1630s, from Latin sequac-, stem of sequax "that follows, following, seeking after," from sequi "to follow" (see sequel) + -ous. Related: Sequaciously; sequaciousness; sequacity (1620s).
sequel (n.): early 15c., "train of followers," from Old French sequelle (14c.), from Late Latin sequela "that which follows, result, consequence," from sequi "to follow, come after, follow after, attend, follow naturally," from PIE root *sekw- (1) "to follow" (source also of Sanskrit sacate "accompanies, follows," Avestan hacaiti, Greek hepesthai "to follow," Lithuanian seku "to follow," Latin secundus "second, the following," Old Irish sechim "I follow"). Meaning "consequence" is attested from late 15c. Meaning "story that follows and continues another" first recorded 1510s.
sequela (n.): plural sequelae, 1793, originally in pathology, from Latin sequela "that which follows, consequence" (see sequel).
sequence (n.): late 14c., "hymn sung after the Hallelujah and before the Gospel," from Old French sequence "answering verses" (13c.), from Medieval Latin sequentia "a following, a succession," from Latin sequentem (nominative sequens), present participle of sequi "to follow" (see sequel). In Church use, a partial loan-translation of Greek akolouthia, from akolouthos "following." General sense of "succession," also "a sequence at cards," appeared 1570s.
sequence (v.): "arrange in a sequence," 1954, from sequence (n.). Related: Sequenced; sequencing.
sequent (adj.): 1550s, "following," from Old French sequent "following, subsequent," from Latin sequentem (nominative sequens) "next, following," present participle of sequi "to follow" (see sequel). As a noun from 1580s.
sequential (adj.): 1816, from Late Latin sequentia (see sequence) + -al (1). Related: Sequentially.
sequester (v.): late 14c., "remove" something, "quarantine, isolate" (someone); "excommunicate;" also intransitive, "separate oneself from," from Old French sequestrer (14c.), from Late Latin sequestrare "to place in safekeeping," from Latin sequester "trustee, mediator," noun use of an adjective meaning "intermediate," which probably is related to sequi "to follow" (see sequel). Meaning "seize by authority, confiscate" is first attested 1510s. Alternative sequestrate (v.) is early 15c., from Latin sequestratus. Related: Sequestered; sequestering.
sequestration (n.): c. 1400, from Late Latin sequestrationem (nominative sequestratio) "a depositing," noun of action from past participle stem of Latin sequestrare (see sequester).
sequin (n.): 1610s, name of a former Italian and Turkish gold coin, from French sequin (17c.), from Italian zecchino, name of a Venetian coin, from zecca "a mint," from Arabic sikkah "a minting die." Meaning "ornamental disc or spangle" is first recorded 1882, from resemblance to a gold coin. Related: Sequined (1890).
sequitur: Latin, literally "it follows."
sequoia (n.): large American coniferous tree, 1857, from Modern Latin tree genus name given 1847 by Austrian botanist Stephan Endlicher (1804-1849), originally to a different tree, the coast redwood, apparently in honor of Sequoya (a.k.a. George Guess, 1760-1843), Cherokee man who invented a system of writing for his people's language, whose name is from Cherokee (Iroquoian) Sikwayi, a word of unknown etymology.

Endlicher was a specialist in conifers, and he also was a philologist. But he never gave an etymology of this name and a search of his papers discovered no mention of Sequoya or the Cherokee writing system, and the connection is an assumption that some botanists have challenged, though no better candidate for a source has yet been found.

The giant sequoia was unseen by Europeans until 1833 and unknown to scientists until 1852. In May 1855, a pair of American botanists named it Taxodium giganteum, but that name was deemed inappropriate for several scientific reasons. Meanwhile, English botanist John Lindley, who had never been to California, in 1853 named it Wellingtonia in honor of the Duke of Wellington. "As high as Wellington towers above his contemporaries, as high towers this California tree above the forest surrounding it. Therefore, it shall bear for all time to come the name Wellingtonia gigantea." This sat poorly with the Americans, and much ink was spilled until a French botanist provided the solution by transferring Endlicher's name. In Britain still popularly called Wellingtonia.
seraglio (n.): "harem," also the name of a former palace of the sultan in Istanbul, 1580s, from Italian seraglio, alteration of Turkish saray "palace, court," from Persian sara'i "palace, inn," from Iranian base *thraya- "to protect" (source also of Avestan thrayeinti "they protect"), from PIE *tra-, variant form of root *tere- (2) "to cross over, pass through, overcome" (see through).

The Italian word probably reflects folk etymology influence of serraglio "enclosure, cage," from Medieval Latin serraculum "bung, stopper" (see serried).
serape (n.): also sarape, type of shawl for men, 1834, from Mexican Spanish sarape, probably from Nahuatl, but exact source difficult to identify source because there is no -r- sound in Nahuatl.
seraph (n.): 1667, first used by Milton (probably on analogy of cherub/cherubim), back-formed singular from Old English seraphim (plural), from Late Latin seraphim, from Greek seraphim, from Hebrew seraphim (only in Isa. vi), plural of *saraph (which does not occur in the Bible), probably literally "the burning one," from saraph "it burned." Seraphs were traditionally regarded as burning or flaming angels, though the word seems to have some etymological sense of "flying," perhaps from confusion with the root of Arabic sharafa "be lofty." Some scholars identify it with a word found in other passages interpreted as "fiery flying serpent."
seraphic (adj.): 1630s, from Church Latin seraphicus, from seraphim (see seraph). Related: Seraphical (1560s).
Serapis: god of the lower world, from Latin, from Greek Serapis, earlier Sarapis, from Egyptian User-hapi, literally "Osiris-Apis."
Serb (n.): 1813, but in reference to the Wends; 1861 as "native of Serbia," from Serbian Srb, perhaps from a root meaning "man." Serbian is attested from 1848 as a noun, 1876 as an adjective. More common in 19c. was Servian.
Serbian (adj.): 1833, from Serb + -ian. As a noun from 1848.
Serbo-: word-forming element meaning "Serbian, Serbian and," from Latinized comb. form of Serb.
sere (adj.): Old English sear "dried up, withered, barren," from Proto-Germanic *sauzas (source also of Middle Low German sor, Dutch zoor "dry"), from PIE root *saus- "dry" (source also of Sanskrit susyati "dries, withers;" Old Persian uška- "dry" (adj.), "land" (n.); Avestan huška- "dry;" Greek auos "dry," auein "to dry;" Latin sudus "dry"). A good word now relegated to bad poetry. Related to sear. Sere month was an old name for "August."
Serena: fem. proper name, from Latin serena, fem. of serenus "clear, bright, fair, joyous" (see serene).