Online Etymology Dictionary

's: suffix forming the possessive case of most Modern English nouns, it gradually was extended in Middle English from Old English -es, the most common genitive inflection of masculine and neuter nouns (cf. dæg "day," genitive dæges "day's").

Old English also had genitives in -e, -re, -an, as well as "mutation-genitives" (cf. boc "book," plural bec), and the -es form never was used in plural (where -a, -ra, -na prevailed), thus avoiding the verbal ambiguity of words like kings'. As a suffix forming some adverbs, it represents the genitive singular ending of Old English masculine and neuter nouns and some adjectives.
In Middle English, both the possessive singular and the common plural forms were regularly spelled es, and when the e was dropped in pronunciation and from the written word, the habit grew up of writing an apostrophe in place of the lost e in the possessive singular to distinguish it from the plural. Later the apostrophe, which had come to be looked upon as the sign of the possessive, was carried over into the plural, but was written after the s to differentiate that form from the possessive singular. By a process of popular interpretation, the 's was supposed to be a contraction for his, and in some cases the his was actually "restored." [Samuel C. Earle, et al, "Sentences and their Elements," New York: Macmillan, 1911]
-s (1): suffix forming almost all Modern English plural nouns, gradually extended in Middle English from Old English -as, the nominative plural and accusative plural ending of certain "strong" masculine nouns (cf. dæg "day," nominative/accusative plural dagas "days"). The commonest Germanic declension, traceable back to the original PIE inflection system, it is also the source of the Dutch -s plurals and (by rhotacism) Scandinavian -r plurals (e.g. Swedish dagar).

Much more uniform today than originally; Old English also had a numerous category of "weak" nouns that formed their plurals in -an, and other strong nouns that formed plurals with -u. Quirk and Wrenn, in their Old English grammar, estimate that 45 percent of the nouns a student will encounter will be masculine, nearly four-fifths of them with genitive singular -es and nominative/accusative plural in -as. Less than half, but still the largest chunk.

The triumphs of -'s possessives and -s plurals represent common patterns in language: using only a handful of suffixes to do many jobs (cf. -ing), and the most common variant squeezing out the competition. To further muddy the waters, it's been extended in slang since 1936 to singulars (e.g. ducks, sweets, babes) as an affectionate or diminutive suffix. Old English single-syllable collectives (sheep, folk) as well as weights, measures, and units of time did not use -s. The use of it in these cases began in Middle English, but the older custom is preserved in many traditional dialects (ten pound of butter; more than seven year ago; etc.).
-s (2): third person singular present indicative suffix of verbs, it represents Old English -es, -as, which began to replace -eð in Northumbrian 10c., and gradually spread south until by Shakespeare's time it had emerged from colloquialism and -eth began to be limited to more dignified speeches.
-saurus: element used in forming dinosaur names, Latinized from Greek sauros "lizard," of unknown origin; possibly related to saulos "twisting, wavering."
-sch-: this letter group can represent five distinct sounds in English; it first was used by Middle English writers to render Old English sc-, a sound now generally pronounced "-sh-." Sometimes it was miswritten for -ch-. It also was taken in from German (schnapps) and Yiddish (schlemiel). In words derived from classical languages, it represents Latin sch-, Greek skh- but in some of these words the spelling is a restoration and the pronunciation does not follow it (cf. schism).
-scope: word-forming element indicating "an instrument for seeing," from Late Latin -scopium, from Greek -skopion, from skopein "to look at, examine" (see scope (n.1)).
-ship: Old English -sciepe, Anglian -scip "state, condition of being," from Proto-Germanic *-skapaz (cf. Old Norse -skapr, Old Frisian -skip, Dutch -schap, German -schaft), from *skap- "to create, ordain, appoint," from PIE root *(s)kep- (see shape (v.)).
-sis: suffix in Greek-derived nouns denoting action, process, state, condition, from Greek -sis, which is identical in meaning with Latin -entia, English -ing (1).
-sk: reflexive suffix in words of Danish origin (e.g. bask, literally "to bathe oneself"), contracted from Old Norse sik, reflexive pronoun corresponding to Gothic sik, Old High German sih, German sich "himself, herself, itself," from PIE root *se- (cf. Latin se "himself").
-some: word-forming element used in making adjectives, from Old English -sum (see some; and cf. Old Frisian -sum, German -sam, Old Norse -samr), related to sama "same."

As a suffix added to numerals meaning "a group of that number" (cf. twosome) it represents Old English sum "some," used after the genitive plural (cf. sixa sum "six-some"), the inflection disappearing in Middle English. Use of some with a number meaning "approximately" also was in Old English.
-sophy: word-forming element meaning "knowledge," from Old French -sophie, from Latin -sophia, from Greek -sophia, from sophia "skill, wisdom, knowledge," of unknown origin.
-stan: "country," source of place names such as Afghanistan, Pakistan, etc., from Persian -stan "country," from Indo-Iranian *stanam "place," literally "where one stands," from PIE *sta-no-, from root *sta- "to stand" (see stet).
-stat: combining form used in forming the names of devices for stabilizing (thermostat, etc.), from Greek statos "standing, stationary," from histanai "to cause to stand," from PIE root *sta- "to stand" (see stet). First used in heliostat "an instrument for causing the sun to appear stationary" (1742).
-ster: Old English -istre, from Proto-Germanic *-istrijon, feminine agent suffix used as the equivalent of masculine -ere. Also used in Middle English to form nouns of action (meaning "a person who ...") without regard for gender.

The genderless agent noun use apparently was a broader application of the original feminine suffix, beginning in the north of England, but linguists disagree over whether this indicates female domination of weaving and baking trades, as represented in surnames such as Webster, Baxter, Brewster, etc. (though spinster clearly represents a female ending). In Modern English, the suffix has been productive in forming derivative nouns (gamester, punster, etc.).
s'mores: snack treat, by 1957 (OED says 1930s), from childish contraction of some more, as in "I'd like some more of those." S'more as a contraction is recorded by 1887.
S.O.L.: initialism from shit out of luck (though sometimes euphemised), 1917, World War I military slang. "Applicable to everything from death to being late for mess" [R. Lord, "Captain Boyd's Battery A.E.F."]
S.P.Q.R.: the insignia of Rome, from Latin Senatus Populusque Romanus "the Senate and People of Rome."
S.T.P.: commercial motor oil additive, probably an initialism of scientifically treated petroleum. As the street name of a type of psychedelic drug, attested from 1967.
S.W.A.T.: 1968, acronym for Special Weapons and Tactics squad or team; or Special Weapons Attack Team.
Sabaoth (n.): early 14c., from Late Latin, from Greek Sabaoth, from Hebrew tzebhaoth "hosts, armies," plural of tzabha "army." A word translated in the Old Testament by the phrase "the Lord of Hosts," but originally left untranslated in the New Testament and in the "Te Deum" in the designation Lord of Sabaoth; often confused with sabbath.
sabbat (n.): "witches' sabbath," 1650s, from French form of sabbath (q.v.); a special application of that word.
sabbatarian (n.): 1610s, "a Christian unusually strict about Sabbath observation," from Latin Sabbatarius (adj.), from Sabbatum (see Sabbath). Meaning "member of a Christian sect which maintained the Sabbath should be observed on the seventh day" is attested from 1640s; earlier sabbatary (1590s).
Sabbath (n.): Old English sabat "Saturday," observed by the Jews as a day of rest, from Latin sabbatum, from Greek sabbaton, from Hebrew shabbath, prop. "day of rest," from shabath "he rested." The Babylonians regarded seventh days as unlucky, and avoided certain activities then; the Jewish observance may have begun as a similar custom.

From the seventh day of the week, it began to be applied early 15c. to the first day (Sunday), a change completed during the Reformation. The original meaning is preserved in Spanish Sabado, Italian Sabbato, and other languages' names for "Saturday." Hung. szombat, Rumanian simbata, French samedi, German Samstag "Saturday" are from Vulgar Latin sambatum, from Greek *sambaton, a vulgar nasalized variant of sabbaton.
sabbatical (adj.): 1640s, "of or suitable for the Sabbath," from Latin sabbaticus, from Greek sabbatikos "of the Sabbath" (see Sabbath). Meaning "a year's absence granted to researchers" (originally one year in seven, to university professors) first recorded 1886 (the thing itself is attested from 1880, at Harvard), related to sabbatical year (1590s) in Mosaic law, the seventh year, in which land was to remain untilled and debtors and slaves released.
saber (n.): "single-edged sword," 1670s, from French sabre "heavy, curved sword" (17c.), alteration of sable (1630s), from German Sabel, probably ultimately from Hung. szablya "saber," literally "tool to cut with," from szabni "to cut."

The Slavic words (cf. Russian sablya, Polish szabla "sword, saber") are perhaps also from German. Italian sciabla seems to be directly from Hungarian. Saber-rattling "militarism" is attested from 1922. Saber-toothed cat (originally tiger) is attested from 1849.
Sabian: an adherent of a religious sect mentioned thrice in the Qu'ran (in which they are classified with Christians, and Jews as "true believers" worth of toleration by Muslims), 1614, from Arabic, of uncertain origin.

Perhaps the reference is to a Gnostic sect akin to the later Mandæans (if the word derives, as some think it does, from Arabic ch'bae "to baptize"); but it has the appearance of derivation from the Sem. root of Hebrew tzabha "host" (see Sabaoth), and as the Sabians were thought in the Middle Ages to have been star-worshippers, it was interpreted as referring to the "host of heaven."
Sabine: people in ancient Italy, late 14c., from Latin Sabinus (in poetic Latin often Sabellus), connected by Tucker to root *sabh- "combine, gather, unite" (cf. Sanskrit sabha "gathering of village community," Russian sebr "neighbor, friend," Gothic sibja, Old High German sippa "blood-relationship, peace, alliance," Old English sibb "relationship, peace").
sable (n.1): "fur or pelt of the European sable" (Martes zibellina), early 15c., from Middle French sable (also martre sable "sable martin"), in reference to the mammal or its fur, borrowed in Old French from a Germanic source (cf. Middle Dutch sabel, Middle Low German sabel, Middle High German zobel), ultimately from a Slavic source (cf. Russian, Czech sobol, Polish soból, the name of the animal), "which itself is borrowed from an East-Asiatic language" [Klein], but Russian sources (e.g. Vasmer) find none of the proposed candidates satisfactory.
sable (n.2): mid-14c., "black" as a heraldic color, commonly identified with sable (n.1), but the animal's fur is brown and this may be a different word of unknown origin; it may reflect a medieval custom (unattested) of dyeing sable fur black. As an adjective from late 14c.
sabotage (n.): 1910, from French sabotage, from saboter "to sabotage, bungle," literally "walk noisily," from sabot "wooden shoe" (13c.), altered (by association with Old French bot "boot") from Middle French savate "old shoe," from an unidentified source that also produced similar words in Old Provençal, Portuguese, Spanish, Italian, Arabic and Basque.

In French, the sense of "deliberately and maliciously destroying property" originally was in reference to labor disputes, but the oft-repeated story that the modern meaning derives from strikers' supposed tactic of throwing old shoes into machinery is not supported by the etymology. Likely it was not meant as a literal image; the word was used in French in a variety of "bungling" senses, such as "to play a piece of music badly."
sabotage (v.): 1912, from sabotage (n). Related: Sabotaged; sabotaging.
saboteur (n.): 1921, a borrowing of the French agent noun from sabotage (see sabotage (n.)).
Sabra (n.): "Jew born in Palestine (or, after 1948, Israel)," 1945, from Modern Hebrew sabrah, literally "prickly pear."
sabre (n.): see saber.
Sabrina: fem. proper name, personified as a nymph by Milton in "Comus" (1634), from a Welsh tale of a maiden drowned in the river Severn by her stepmother, a legend found in Geoffrey of Monmouth and Giraldus Cambrensis. The name appears to be merely the Romanized form of the name of the River Severn (Welsh Hafren, Habren), which is Celtic and of unknown origin; it perhaps means "boundary." Sabrina neckline is from the 1954 film "Sabrina" starring Audrey Hepburn.
sac (n.): "biological pocket," 1741, from French sac, from Latin saccus "bag" (see sack (n.1)).
Sacagawea: also Sacajawea, name of the Shoshoni woman who accompanied the Lewis & Clark expedition.
She had been a captive among the Hidatsas (a Siouan people), and her Hidatsa name was tsaka'aka wi'a, lit. 'bird woman' (Hartley, 2002). Her Shoshoni name, rendered as Sacajawea and translated 'boat launcher,' may have been a folk-etymological transformation of the Hidatsa term (Shaul, 1972). [Bright]
saccade: mid-18c., from French saccade "a jerk," from obsolete saquer "to shake, pull," dialectal variant of Old French sachier, ultimately from Latin saccus "sack."
saccharin (n.): "white crystalline compound used as a sugar substitute," 1885, from German, coined by chemist C. Fahlberg, 1879, who discovered it by accident, from Latin saccharon (see saccharine). Marketed from 1887 as saccharine.
saccharine (adj.): 1670s, "of or like sugar," from Medieval Latin saccharum "sugar," from Latin saccharon, from Greek sakkharon, from Pali sakkhara, from Sanskrit sarkara "gravel, grit" (see sugar). Metaphoric sense of "overly sweet" first recorded 1841. For the sugar substitute, see saccharin.
sacerdotal (adj.): c.1400, from Old French sacerdotal, from Latin sacerdotalis "of or pertaining to a priest," from sacerdos (genitive sacerdotis) "priest," literally "offerer of sacrifices," from sacer "holy" (see sacred) + stem of dare "to give" (see date (n.1)).
sachem (n.): chief of an American Indian tribe, 1620s, from Narragansett (Algonquian) sachimau "chief, ruler," cognate with Abenaki sangman, Delaware sakima, Micmac sakumow, Penobscot sagumo (source of sagamore, 1610s). Applied jocularly to a prominent member of any society from 1680s; specific political use in U.S. is from 1890, from its use as the title of the 12 high officials of the Tammany Society of New York.
sachet (n.): "small perfumed bag," 1838, from French sachet (12c.), diminutive of sac (see sac). A reborrowing of a word that had been used 15c. in the sense "small bag, wallet."
sack (n.1): "large bag," Old English sacc (West Saxon), sec (Mercian), sæc (Old Kentish) "large cloth bag," also "sackcloth," from Proto-Germanic *sakkiz (cf. Middle Dutch sak, Old High German sac, Old Norse sekkr, but Gothic sakkus probably is directly from Greek), an early borrowing from Latin saccus (cf. Old French sac, Spanish saco, Italian sacco), from Greek sakkos, from Semitic (cf. Hebrew saq "sack").

The wide spread of the word is probably due to the story of Joseph. Slang meaning "bunk, bed" is from 1825, originally nautical. The verb meaning "go to bed" is recorded from 1946.
sack (n.2): "a dismissal from work," 1825, from sack (n.1), perhaps from the notion of the worker going off with his tools in a bag; the original formula was to give (someone) the sack. It is attested earlier in French (on luy a donné son sac, 17c.) and Dutch (iemand de zak geven). The verb is recorded from 1841. Related: Sacked; sacking.
sack (n.3): "sherry," 1530s, alteration of French vin sec "dry wine," from Latin siccus "dry" (see siccative).
sack (v.1): "to plunder," 1540s, from Middle French sac, in the phrase mettre à sac "put it in a bag," a military leader's command to his troops to plunder a city (parallel to Italian sacco, with the same range of meaning), from Vulgar Latin *saccare "to plunder," originally "to put plundered things into a sack," from Latin saccus "bag" (see sack (n.1)). The notion is probably of putting booty in a bag. This is the root of the verb in the U.S. football sense (1969).
sackbut (n.): medieval wind instrument, c.1500, from French saquebute, a bass trumpet with a slide like a trombone; presumably identical with Old North French saqueboute (14c.), "a lance with an iron hook for pulling down mounted men," said to be from Old North French saquier "to pull, draw" + bouter "to thrust."

In Dan. iii:5, used wrongly to translate Aramaic sabbekha, name of a stringed instrument (translated correctly in Septuagint as sambuke, and in Vulgate as sambuca, both names of stringed instruments, and probably ultimately cognate with the Aramaic word). The error began with Coverdale (1535), who evidently thought it was a wind instrument and rendered it with shawm; the Geneva translators, evidently following Coverdale, chose sackbut because it sounded like the original Aramaic word, and this was followed in KJV and Revised versions.
sackcloth (n.): penitential garb, c.1300, from sack (n.1) + cloth. In the Biblical sense it was of goats' or camels' hair, the coarsest possible clothing.
sacral (adj.): 1767, in anatomy, from Modern Latin sacralis, from sacrum, the bone (see sacrum). In anthropology, from 1882, from Latin sacrum "sacred thing, rite" (see sacred). Related: sacralization.