's Look up 's at Dictionary.com
suffix forming the possessive singular case of most Modern English nouns; its use gradually was extended in Middle English from Old English -es, the most common genitive inflection of masculine and neuter nouns (such as dæg "day," genitive dæges "day's").

Old English also had genitives in -e, -re, -an, as well as "mutation-genitives" (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'.
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]
As a suffix forming some adverbs, it represents the genitive singular ending of Old English masculine and neuter nouns and some adjectives.
-s (1) Look up -s at Dictionary.com
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 (such as 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 (such as 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 (such as -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 (such as 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) Look up -s at Dictionary.com
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 Look up -saurus at Dictionary.com
element used in forming dinosaur names, from Latinized comb. form of Greek sauros "lizard," of unknown origin; possibly related to saulos "twisting, wavering."
-sch- Look up -sch- at Dictionary.com
this letter group can represent five distinct sounds in English; it first was used by Middle English writers to render Old English sc-, the pronunciation of which then simplified to "-sh-" (an evolution that also took place in Middle Dutch and Middle High German). 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 (such as schism) the English spelling is a restoration and the pronunciation does not follow it.
-scope Look up -scope at Dictionary.com
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)).
-scopy Look up -scopy at Dictionary.com
word-forming element meaning "viewing, examining, observing," from Modern Latin -scopium, from Greek -skopion, from skopein "to look at, examine" (see scope (n.1)).
-ship Look up -ship at Dictionary.com
word-forming element meaning "quality, condition; act, power, skill; office, position; relation between," Middle English -schipe, from Old English -sciepe, Anglian -scip "state, condition of being," from Proto-Germanic *-skapaz (cognates: Old Norse -skapr, Danish -skab, Old Frisian -skip, Dutch -schap, German -schaft), from *skap- "to create, ordain, appoint," from PIE root *(s)kep-, forming words meaning "to cut, scrape, hack" (see shape (v.)).
-sis Look up -sis at Dictionary.com
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 Look up -sk at Dictionary.com
reflexive suffix in words of Danish origin (such as 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 *s(w)e- (source of Latin se "himself;" see idiom).
-some (1) Look up -some at Dictionary.com
word-forming element used in making adjectives from nouns or adjectives (and sometimes verbs) and meaning "tending to; causing; to a considerable degree," from Old English -sum, identical with som (see some). Cognate with Old Frisian -sum, German -sam, Old Norse -samr; also related to same.
-some (2) Look up -some at Dictionary.com
suffix added to numerals meaning "a group of (that number)," as in twosome, from pronoun use of Old English sum "some" (see some). Originally a separate word used with the genitive plural (as in sixa sum "six-some"); the inflection disappeared in Middle English and the pronoun was absorbed. Use of some with a number meaning "approximately" also was in Old English.
-some (3) Look up -some at Dictionary.com
word-forming element meaning "the body," Modern Latin, from Greek soma "the body" (see somato-).
-sophy Look up -sophy at Dictionary.com
word-forming element meaning "knowledge," from Old French -sophie, from Latin -sophia, from Greek -sophia, from sophia "skill, wisdom, knowledge" (see Sophia).
-spirited Look up -spirited at Dictionary.com
"having a spirit (of a specified type)," from spirit (n.).
-spoken Look up -spoken at Dictionary.com
in compounds, "speaking" (in a certain way), late-15c., from past participle of speak (v.).
-stan Look up -stan at Dictionary.com
place-name element in Afghanistan, Pakistan, etc., from Persian -stan "country," from Indo-Iranian *stanam "place," literally "where one stands," from PIE *sta-no-, suffixed form of root *sta- "to stand" (see stet).
-stat Look up -stat at Dictionary.com
word-forming element used in making names of devices for stabilizing or regulating (such as thermostat), from Greek statos "standing, stationary," from PIE *ste-to-, suffixed form of root *sta- "to stand" (see stet). First used in heliostat "an instrument for causing the sun to appear stationary" (1742). Related: -static.
-ster Look up -ster at Dictionary.com
Old English -istre, from Proto-Germanic *-istrijon, feminine agent suffix used as the equivalent of masculine -ere (see -er (1)). 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 probably carries an originally female ending). Also whitester "one who bleaches cloth." In Modern English, the suffix has been productive in forming derivative nouns (gamester, punster, etc.).
s'mores Look up s'mores at Dictionary.com
snack treat, 1937, 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. Look up S.O.L. at Dictionary.com
initialism (acronym) 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. Look up S.P.Q.R. at Dictionary.com
the insignia of Rome, from Latin Senatus Populusque Romanus "the Senate and People of Rome."
S.T.D. Look up S.T.D. at Dictionary.com
1975 as an abbreviation of sexually transmitted disease. Earlier it was an abbreviation of Latin Sacrosanctae Theologiae Doctor "Doctor of Sacred Theology."
S.W.A.T. Look up S.W.A.T. at Dictionary.com
also SWAT, 1968, acronym said to be for Special Weapons and Tactics squad or team; or Special Weapons Attack Team.
s/he (pron.) Look up s/he at Dictionary.com
artificial genderless pronoun, attested from 1977; from he + she.
Saar Look up Saar at Dictionary.com
river in western Germany, from PIE root *ser- (2) "to run, flow" (see serum).
Sabaoth (n.) Look up Sabaoth at Dictionary.com
early 14c., from Late Latin, from Greek Sabaoth, rendering Hebrew tzebhaoth "hosts, armies," plural of tzabha "army," from tzaba "he waged war, he served." A word translated in English 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.
sabaton (n.) Look up sabaton at Dictionary.com
type of armored foot-covering, also sabbaton, early 14c., ultimately from Provençal sabato, equivalent of French savate (see sabotage (n.)).
sabbat (n.) Look up sabbat at Dictionary.com
"witches' sabbath," 1650s, special application of the French form of sabbath.
Sabbatarian (n.) Look up Sabbatarian at Dictionary.com
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). Related: Sabbatartianism.
Sabbath (n.) Look up Sabbath at Dictionary.com
Old English sabat "Saturday as a day of rest," as observed by the Jews, from Latin sabbatum, from Greek sabbaton, from Hebrew shabbath, properly "day of rest," from shabath "he rested." Spelling with -th attested from late 14c., not widespread until 16c.

The Babylonians regarded seventh days as unlucky, and avoided certain activities then; the Jewish observance might have begun as a similar custom. Among European Christians, from the seventh day of the week it began to be applied early 15c. to the first day (Sunday), "though no definite law, either divine or ecclesiastical, directed the change" [Century Dictionary], but elaborate justifications have been made. The change was driven by Christians' celebration of the Lord's resurrection on the first day of the week, a change completed during the Reformation.

The original meaning is preserved in Spanish Sabado, Italian Sabbato, and other languages' names for "Saturday." Hungarian szombat, Rumanian simbata, French samedi, German Samstag "Saturday" are from Vulgar Latin sambatum, from Greek *sambaton, a vulgar nasalized variant of sabbaton. Sabbath-breaking attested from 1650s.
sabbatical (adj.) Look up sabbatical at Dictionary.com
1640s, "of or suitable for the Sabbath," from Latin sabbaticus, from Greek sabbatikos "of the Sabbath" (see Sabbath). Noun meaning "a year's absence granted to researchers" (originally one year in seven, to university professors) is from 1934, short for sabbatical year, etc., 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.
Sabean (n.) Look up Sabean at Dictionary.com
inhabitant of the region of Arabia now known as Yemen, from Latin Sabaeus, from Greek Sabaios "the people of Saba," the region's capital city, from Arabic Saba'. In ancient times it was an important transit point for spices, perfumes, precious stones, etc., imported to Europe from India.
saber (n.) Look up saber at Dictionary.com
type of single-edged sword, 1670s, from French sabre "heavy, curved sword" (17c.), alteration of sable (1630s), from German Sabel, Säbel, probably ultimately from Hungarian szablya "saber," literally "tool to cut with," from szabni "to cut."

The Balto-Slavic words (Russian sablya, Polish szabla "sword, saber," Lithuanian shoble) perhaps also are 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 (n.) Look up Sabian at Dictionary.com
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), 1610s, from Arabic, of uncertain origin. As an adjective from 1748.

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," Aramaic tzebha "he dipped, dyed"); but it has the appearance of derivation from the Semitic 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." Related: Sabaism.
Sabin Look up Sabin at Dictionary.com
in reference to polio vaccine, 1955, from name of Russian-born U.S. microbiologist Albert B. Sabin (1906-1993).
Sabine (adj.) Look up Sabine at Dictionary.com
"pertaining to a people in ancient Italy," late 14c., from Latin Sabinus (in poetic Latin often Sabellus), perhaps literally "of its own kind" and connected to root of 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;" see sibling).
sable (n.1) Look up sable at Dictionary.com
"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 Germanic (Middle Dutch sabel, Middle Low German sabel, Middle High German zobel), ultimately from a Slavic source (compare Russian, Czech sobol, Polish soból, the name of the animal), "which itself is borrowed from an East-Asiatic language" [Klein], but Russian sources (such as Vasmer) find none of the proposed candidates satisfactory.
sable (n.2) Look up sable at Dictionary.com
"black" as a heraldic color, early 14c., commonly identified with sable (n.1), but the animal's fur is brown and this may be a different word of unknown origin; or it might reflect a medieval custom (unattested) of dyeing sable fur black. As an adjective from late 14c. Emblematic of mourning or grief from c. 1600; c. 1800 as "black" with reference to Africans and their descendants, often with mock dignity.
sabotage (n.) Look up sabotage at Dictionary.com
1907 (from 1903 as a French word in English), 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 (zapata), Italian (ciabatta), Arabic (sabbat), and Basque (zapata).

In French, and at first in English, the sense of "deliberately and maliciously destroying property" originally was in reference to labor disputes, but the oft-repeated story (as old as the record of the word in English) that the modern meaning derives from strikers' supposed tactic of throwing 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." This, too, was the explanation given in some early usages.
SABOTAGE [chapter heading] The title we have prefixed seems to mean "scamping work." It is a device which, we are told, has been adopted by certain French workpeople as a substitute for striking. The workman, in other words, purposes to remain on and to do his work badly, so as to annoy his employer's customers and cause loss to his employer. ["The Liberty Review," January 1907]

You may believe that sabotage is murder, and so forth, but it is not so at all. Sabotage means giving back to the bosses what they give to us. Sabotage consists in going slow with the process of production when the bosses go slow with the same process in regard to wages. [Arturo M. Giovannitti, quoted in report of the Sagamore Sociological Conference, June 1907]

In English, "malicious mischief" would appear to be the nearest explicit definition of "sabotage," which is so much more expressive as to be likely of adoption into all languages spoken by nations suffering from this new force in industry and morals. Sabotage has a flavor which is unmistakable even to persons knowing little slang and no French .... ["Century Magazine," November 1910]
sabotage (v.) Look up sabotage at Dictionary.com
1912, from sabotage (n). Related: Sabotaged; sabotaging.
saboteur (n.) Look up saboteur at Dictionary.com
1912 (from 1909 as a French word in English), a borrowing of the French agent noun from sabotage (see sabotage (n.)).
Sabra (n.) Look up Sabra at Dictionary.com
"Jew born in Palestine (or, after 1948, Israel)," 1945, from Modern Hebrew sabrah, literally "prickly pear."
sabre (n.) Look up sabre at Dictionary.com
see saber.
Sabrina Look up Sabrina at Dictionary.com
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 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.
sabulous (adj.) Look up sabulous at Dictionary.com
"sandy," 1630s, from Latin sabulosus, from sabulum "coarse sand" (see sand (n.)).
sac (n.) Look up sac at Dictionary.com
"biological pocket," 1741, from French sac, from Latin saccus "bag" (see sack (n.1)).
Sac Look up Sac at Dictionary.com
central Algonquian people who lived near the upper Mississippi before the Black Hawk War of 1832, from French Canadian Saki, probably a shortened borrowing of Ojibwa (Algonquian) /osa:ki:/, literally "person of the outlet" (of the Saginaw River, which itself contains their name, and means literally "in the Sauk country").
Sacagawea Look up Sacagawea at Dictionary.com
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]
Her image appeared on U.S. dollar coins from 2000.
saccade (n.) Look up saccade at Dictionary.com
1705, from French saccade "a jerk," from obsolete saquer "to shake, pull," dialectal variant of Old French sachier, ultimately from Latin saccus "sack" (see sack (n.1)). Related: Saccadic.