Online Etymology Dictionary

silage (n.): "fodder packed in a silo," 1884, alteration (probably by influence of silo) of ensilage (1881), from French ensilage, from ensiler "put in a silo," from Spanish ensilar (see silo).
Silas: masc. proper name, from Late Latin, from Greek Silas, contraction of Silouanos, transliteration of Latin Silvanus, a name that literally means "living in the woods," from silva "wood."
silence (n.): early 13c., from Old French silence "absence of sound," from Latin silentium "a being silent," from silens, present participle of silere "be quiet or still," of unknown origin. Replaced Old English swige. The verb (transitive) is attested from 1590s, from the noun. Silencer "mechanism that stifles the sound of a motor or firearm" first recorded 1898.
silent (adj.): 1560s, from Latin silentem, from silere (see silence). Phrase strong, silent (type) is attested from 1905. Silent majority in the political sense of "mass of people whose moderate views are not publicly expressed and thus overlooked" is first attested 1955 in a British context and was used by John F. Kennedy but is most associated in U.S. with the rhetoric of the Nixon administration (1969-74).
It is time for America's silent majority to stand up for its rights, and let us remember the American majority includes every minority. America's silent majority is bewildered by irrational protest. [Spiro T. Agnew, May 9, 1969]
In Victorian use, the phrase meant "the dead" (1874).
Silenus: 1710, from Greek seilenos, foster-father of Bacchus and leader of the satyrs.
silhouette (n.): 1798, from French silhouette, in reference to Étienne de Silhouette (1709-1767), French minister of finance in 1759. Usually said to be so called because it was an inexpensive way of making a likeness of someone, a derisive reference to Silhouette's petty economies to finance the Seven Years' War, which were unpopular among the nobility. But other theories are that it refers to his brief tenure in office, or the story that he decorated his chateau with such portraits.
Silhouette portraits were so called simply because they came into fashion in the year (1759) in which M. de Silhouette was minister. [A. Brachet, "An Etymological Dictionary of the French Language," transl. G.W. Kitchin, 1882]
The verb is recorded from 1876. The family name is a Frenchified form of a Basque surname; Arnaud de Silhouette, the finance minister's father, was from Biarritz in the French Basque country; the southern Basque form of the name would be Zuloeta or Zulueta, which contains the suffix -eta "abundance of" and zulo "hole" (possibly here meaning "cave").
silica: "hard silicon dioxide," 1801, Modern Latin, from Latin silex (genitive silicis) "flint, pebble," on model of alumina, soda.
silicate (n.): 1811, from silica + -ate (3).
silicon: nonmetallic element, 1817, coined by British chemist Thomas Thomson from silica (silicon dioxide), from which it was isolated. The name is patterned on carbon, etc. Silicon chip first attested 1965; Silicon Valley for the Santa Clara Valley south of San Francisco, U.S., first attested 1974, from the concentration of manufacturers of silicon chips used in computers, watches, etc.
silicone: coined 1863 in German from silico-, comb. form indicating the presence of silicon, + -one.
silk (n.): Old English sioloc, seoloc "silk," ultimately from an Asian word (cf. Chinese si "silk," Manchurian sirghe, Mongolian sirkek) borrowed into Greek as serikos "silken," serikon "silk" (cf. Greek Seres, a name for an oriental people from whom the Greeks got silk). Also found in Old Norse silki but not elsewhere in Germanic.

According to some sources, the use of -l- instead of -r- in the Balto-Slavic form of the word (cf. Old Church Slavonic šelku, Lithuanian šilkai) passed into English via the Baltic trade and may reflect a Chinese dialectal form, or a Slavic alteration of the Greek word. But the Slavic linguist Vasmer dismisses that, based on the initial sh- in the Slavic words, and suggests the Slavic words are from Scandinavian rather than the reverse.

Western cultivation began 552 C.E., when agents from Byzantium impersonating monks smuggled silkworms and mulberry leaves out of China. In reference to the "hair" of corn, 1660s, American English. Figurative use of silk-stocking (adj.) for "wealthy" is attested from 1798, American English. Silk-screen is first attested 1930. Silk road so called in English from 1931.
silken: Old English seolcen; see silk + -en (2).
silkworm: Old English seolcwyrm; see silk + worm.
silky: 1610s, from silk + -y (2). Related: Silkily; silkiness.
sill: Old English syll "beam, large timber serving as a foundation of a wall," from Proto-Germanic *suljo (cf. Old Norse svill "framework of a building," Middle Low German sull, Old High German swelli, German Schwelle "sill"), perhaps from PIE root *swel- "post, board" (cf. Greek selma "beam"). Meaning "lower horizontal part of a window opening" is recorded from early 15c.
sillabub: 1530s, of unknown origin. Drink or dish of milk and wine or cider, often sweetened. Figurative sense of "floridly vapid prose" is from 1706.
silly (adj.): Old English gesælig "happy" (related to sæl "happiness"), from West Germanic *sæligas (cf. Old Norse sæll "happy," Gothic sels "good, kindhearted," Old Saxon salig, Middle Dutch salich, Old High German salig, German selig "blessed, happy, blissful"), from PIE root *sel- "happy" (cf. Latin solari "to comfort").

The word's considerable sense development moved from "blessed" to "pious," to "innocent" (c.1200), to "harmless," to "pitiable" (late 13c.), to "weak" (c.1300), to "feeble in mind, lacking in reason, foolish" (1570s). Further tendency toward "stunned, dazed as by a blow" (1886) in knocked silly, etc. Silly season in journalism slang is from 1861 (August and September, when newspapers compensate for a lack of hard news by filling up with trivial stories). Silly Putty trademark claims use from July 1949.
silo (n.): 1835, from Spanish silo, from Latin sirum (nominative sirus), from Greek siros "a pit to keep corn in." Or, alternately, the Spanish word is from a pre-Roman Iberian language word represented by Basque zilo, zulo "dugout, cave or shelter for keeping grain." Meaning "underground housing and launch tube for a guided missile" is attested from 1958.
Siloam: pool and spring outside Jerusalem (John ix:7), from Late Latin, from New Testament Greek, from Hebrew shiloach, literally "sending forth," from shalach "to send."
silphium: plant genus, 1771, from Latin, from Greek Silphion, name of a North African Mediterranean plant whose identity has been lost, the gum or juice of which was prized by the ancients as a condiment and a medicine. Probably of African origin.
silt: mid-15c., originally "sediment deposited by seawater," probably from Middle Low German or Middle Dutch silte, sulte "salt marsh, brine," related to Old English sealt, Old High German sulza "saltwater," German Sulze "brine" (see salt). The verb meaning "to become choked with silt" (of river channels, harbors, etc.) is attested from 1799.
Silurian: 1708, "pertaining to the Silures," from Latin Silures "ancient British tribe inhabiting southeast Wales." Geological sense is from 1835, coined by Sir Roderick Impey Murchison (1792-1871) because rocks of this period are especially frequent in Wales.
silver (n.): Old English seolfor "silver," from Proto-Germanic *silubra- (cf. Old Saxon silvbar, Old Norse silfr, Middle Dutch silver, Dutch zilver, Old High German sillabar, German silber, Gothic silubr), from a common Germanic/Balto-Slavic term (cf. Old Church Slavonic s(u)rebo, Russian serebro, Polish srebro, Lithuanian sidabras "silver"), possibly from a language of Asia Minor. Perhaps from Akkadian sarpu "silver," literally "refined silver," related to sarapu "to refine, smelt." Chemical abbreviation Ag is from Latin argentum "silver," from the PIE root (see argent).
silver (v.): "to cover or plate with silver," mid-15c., from silver (n.). Related: Silvered; silvering.
silver bullet: "very effective, almost magical remedy," 1808. The belief in the magical power of silver weapons to conquer foes goes back at least to ancient Greece (e.g. Delphic Oracle's advice to Philip of Macedon).
silver lining: a "bright side" which proverbially accompanies even the darkest trouble; by 1843, apparently from oft-quoted lines from Milton's "Comus," where the silver lining is the light of the moon shining from behind the cloud.
Was I deceived? or did a sable cloud
Turn forth her silver lining on the night?
I did not err, there does a sable cloud,
Turn out her silver lining on the night
And casts a gleam over this tufted grove.
To which Thomas Warton added the commentary: "When all succour ſeems to be lost, Heaven unexpectedly presents the ſilver lining oſ a ſable cloud to the virtuous."
silver screen (n.): 1921, originally in reference to movie house projection screens colored with metallic paint to be more reflective. Transferred sense of "movies generally" is attested from 1924.
Silver Star: U.S. military decoration awarded for gallantry in action, originally (1918) a small badge worn on the ribbon of a campaign medal; as a distinct medal, it was established Aug. 8, 1932.
silverfish (n.): 1703, in reference to various types of silver-colored fish (cf. German Silberfisch, Dutch zilvervisch); from silver + fish (n.). In reference to a type of insect (also known as springtail), it is attested from 1855.
silverware: 1860, from silver + ware (n.).
Simeon: masc. proper name, Biblical second son of Jacob and Leah; also a tribe of Israel; see Simon.
simian (adj.): "pertaining to monkeys or apes," c.1600, from Latin simia "ape," from simus "snub-nosed," from Greek simos "snub-nosed, bent upward," of unknown origin. The noun meaning "an ape or monkey" first is attested in 1880.
similar (adj.): 1610s (earlier similary, 1560s), from French similaire, from an extended form of Latin similis "like," from Old Latin semol "together," from PIE root *sem-/*som- "same" (see same).
similarity (n.): 1660s, from similar + -ity, or from French similarité. Related: Similarities.
simile (n.): late 14c., from Latin simile "a like thing," neuter of similis "like" (see similar). "A simile, to be perfect, must both illustrate and ennoble the subject." [Johnson].
similitude (n.): late 14c., from Old French similitude, from Latin similitudinem (nominative similitudo) "likeness," from similis "like" (see similar).
simmer (v.): 1650s, alteration of simperen "to simmer" (late 15c.), possibly of imitative origin. Figurative sense, of feelings, "to be agitated" is from 1764. Opposite sense, in simmer down, first recorded 1871.
I must and will keep shady and quiet till Bret Harte simmers down a little. [Mark Twain, letter, 1871]
Related: Simmered; simmering.
simnel (n.): "sweet cake," c.1200, from Old French simenel "fine wheat flour," by dissimilation from Vulgar Latin *siminellus, a diminutive of Latin simila "fine flour" (see semolina).
simoleon (n.): slang for "a dollar," 1895, American English, of unknown origin; related sambolio is attested from 1886.
Simon: masc. proper name, from Latin, from Greek Symeon, from Hebrew Shim'on, literally "hearkening, hearing," from shama "he heard." In English Old Testaments, usually printed as Simeon, but in New Testament almost always as Simon. Confused with Greek masc. proper name Simon, which is from simos "snub-nosed."
simon-pure (adj.): 1815, from the true Simon Pure "the genuine person or thing" (1795), from Simon Pure, name of a Quaker who is impersonated by another character (Colonel Feignwell) in part of the comedy "A Bold Stroke for a Wife" (1717) by Susannah Centlivre, English dramatist and actress. The real Simon Pure is dealt with as an imposter in the play and is believed only after he has proved his identity.
simonize (v.): 1934, from simoniz, trademark for a type of car polish invented by George Simons, who along with Elmer Rich of the Great Northern Railway organized Simons Manufacturing Company to sell it in Chicago, U.S.A., in 1910. Rich and his brother, R.J. Rich, acquired sole ownership two years later.
simony (n.): early 13c., "the buying or selling of sacred things," from Old French simonie, from Late Latin simonia, from Simon Magus, the Samaritan magician who was rebuked by Peter when he tried to buy the power of conferring the Holy Spirit (Acts viii:18-20).
simoom (n.): "hot, dry desert wind," 1790, from Arabic samum "a sultry wind," literally "poisonous," from samma "he poisoned," from sam "poison."
simp (n.): 1903, circus slang shortening of simpleton.
simpatico (adj.): 1864, from Spanish simpatico "sympathetic," from simpatia "sympathy," or from Italian simpatico, from simpatia, both ultimately from Latin sympathia (see sympathy).
simper (v.): 1560s, perhaps from a Scandinavian source (e.g. dialectal Danish semper "affected, coy, prudish") or Middle Dutch zimperlijk "affected, coy, prim." Related: Simpered; simpering.
simple (adj.): early 13c., "humble, ignorant," from Old French simple, from Latin simplus "single," variant of simplex (see simplex). Sense evolved to "lowly, common" (late 13c.), then "mere, pure" (c.1300). As opposite of composite it dates from early 15c.; as opposite of complicated it dates from 1550s. Disparaging sense (mid-14c.) is from notion of "devoid of duplicity."
simpleton (n.): 1640s, jocular formation from simple and -ton, suffix extracted from surnames.
simplex (adj.): "characterized by a single part," 1590s, from Latin simplex "single, simple," from PIE root *sem- "one, together" (cf. Latin semper "always," literally "once for all;" Sanskrit sam "together;" see same) + *plac- "-fold." The noun is attested from 1892.