Silurian (adj.)
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.
silvan (adj.)
see sylvan.
silver (v.)
"to cover or plate with silver," mid-15c., from silver (n.). Meaning "to tinge with gray" (of hair) is from c. 1600. Related: Silvered; silvering.
silver (n.)
Old English seolfor, Mercian sylfur "silver; money," from Proto-Germanic *silubra- (source also of Old Saxon silvbar, Old Frisian selover, Old Norse silfr, Middle Dutch silver, Dutch zilver, Old High German silabar, German silber "silver; money," Gothic silubr "silver"), from a common Germanic/Balto-Slavic word (source also of Old Church Slavonic s(u)rebo, Russian serebro, Polish srebro, Lithuanian sidabras "silver") of uncertain relationship and origin. According to Klein's sources, possibly from a language of Asia Minor, perhaps from Akkadian sarpu "silver," literally "refined silver," related to sarapu "to refine, smelt."

As an adjective from late Old English (also silvern). As a color name from late 15c. Of voices, words, etc., from 1520s in reference to the metal's pleasing resonance; silver-tongued is from 1590s. The silver age (1560s) was a phrase used by Greek and Roman poets. Chemical abbreviation Ag is from Latin argentum "silver," from the usual PIE word for the metal (see argent), which is missing in Germanic.
silver bullet (n.)
"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 (as in Delphic Oracle's advice to Philip of Macedon).
silver lining (n.)
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 (similar formation in German Silberfisch, Dutch zilvervisch); from silver (adj.) + fish (n.). In reference to a type of household insect damaging to books, wallpaper, etc. (also known as silvertail and furniture-bug), it is attested from 1855.
silvern (adj.)
Middle English silveren, from Old English seolfren "made of silver;" see silver (n.) + -en (2). Similar formation in German silbern, Dutch zilveren. Fallen from use in English except in poetry.
silversmith (n.)
Old English seolfursmið; see silver (n.) + smith (n.).
silverware
1860, from silver (n.) + ware (n.).
silvery (adj.)
late 14c., from silver (n.) + -y (2). Related: Silveriness.
Simeon
masc. proper name, Biblical second son of Jacob and Leah; also a tribe of Israel; see Simon.
simian (adj.)
"characteristic of monkeys or apes," c. 1600, from Latin simia "ape," from simus "snub-nosed," from Greek simos "snub-nosed" (like the Scythians), also a masculine proper name, of unknown origin. Biological meaning "pertaining to monkeys" is from 1863. The noun meaning "an ape or monkey" first is attested in 1880.
similar (adj.)
"having characteristics in common," 1610s (earlier similary, 1560s), from French similaire, from a Medieval Latin extended form of Latin similis "like, resembling, of the same kind," from Old Latin semol "together," from PIE root *sem- (1) "one; as one, together with." The noun meaning "that which is similar" is from 1650s. Related: Similarly.
similarity (n.)
"state of being similar," 1660s, from similar + -ity, or from French similarité. Related: Similarities "points of resemblance" (1838).
simile (n.)
late 14c., from Latin simile "a like thing; a comparison, likeness, parallel," neuter of similis "like, resembling, of the same kind" (see similar). Both things must be mentioned and the comparison directly stated. To Johnson, "A simile, to be perfect, must both illustrate and ennoble the subject."
similitude (n.)
late 14c., from Old French similitude "similarity, relationship, comparison" (13c.) and directly from Latin similitudinem (nominative similitudo) "likeness, resemblance," from similis "like, resembling, of the same kind" (see similar).
simmer (v.)
1650s, alteration of simperen "to simmer" (late 15c.), possibly imitative; not thought to be connected to simper (v.). OED says the change is "probably due to a feeling of phonetic appropriateness." Figurative sense, of feelings, "to be agitated" is from 1764. Opposite sense, in simmer down, first recorded 1871, probably from the notion of moving from a full boil to a mere simmer.
I must and will keep shady and quiet till Bret Harte simmers down a little. [Mark Twain, letter, 1871]
Related: Simmered; simmering. The noun meaning "a condition of simmering" is from 1809.
simnel (n.)
"sweet cake," c. 1200, from Old French simenel "fine wheat flour; flat bread cake, Lenten cake," probably by dissimilation from Vulgar Latin *siminellus (also source of Old High German semala "the finest wheat flour," German Semmel "a roll"), 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; perhaps this was altered based on Napoleon, name of a late 19c. French gold coin. And compare Latin coin-names semodius "half a modius," simbella "coin worth half a libella."
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.)
1921, 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.)
c. 1200, "the sin of buying or selling sacred things," from Old French simonie "selling of church offices" (12c.), 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). Related: Simoniac; simoniacal.
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 (in fem. form simpatica), from Spanish simpatico "sympathetic," from simpatia "sympathy," or from Italian simpatico, from simpatia, both ultimately from Latin sympathia (see sympathy).
simper (v.)
1560s, "to smile in an affected and silly way," perhaps from a Scandinavian source (such as dialectal Danish semper "affected, coy, prudish") or Middle Dutch zimperlijk "affected, coy, prim," of unknown origin. Related: Simpered; simpering. As a noun, 1590s, from the verb.
simpering (adj.)
1580s, present participle adjective from simper (v.). Related: Simperingly.
simple (adj.)
c. 1200, "free from duplicity, upright, guileless; blameless, innocently harmless," also "ignorant, uneducated; unsophisticated; simple-minded, foolish," from Old French simple (12c.) "plain, decent; friendly, sweet; naive, foolish, stupid," hence "wretched, miserable," from Latin simplus from PIE compound *sm-plo-, from root *sem- (1) "one; as one, together with" + *-plo- "-fold."

Sense of "free from pride, humble, meek" is mid-13c. As "consisting of only one substance or ingredient" (opposite of composite or compounded) it dates from late 14c.; as "easily done" (opposite of complicated) it dates from late 15c.

From mid-14c. as "unqualified; mere; sheer;" also "clear, straightforward; easily understood." From late 14c. as "single, individual; whole." From late 14c. of clothing, etc., "modest, plain, unadorned," and of food, "plain, not sumptuous." In medicine, of fractures, etc., "lacking complications," late 14c. As a law term, "lacking additional legal stipulations, unlimited," from mid-14c.

In Middle English with wider senses than recently, such as "inadequate, insufficient; weak, feeble; mere; few; sad, downcast; mournful; of little value; low in price; impoverished, destitute;" of hair, "straight, not curly." As noun, "an innocent or a guileless person; a humble or modest person" (late 14c.), also "an uncompounded substance." From c. 1500 as "ignorant people."
simple-minded (adj.)
1744, from simple (adj.) + -minded. Related: Simple-mindedly; simple-mindedness.
simpleness (n.)
14c., "absence of pride," from simple (adj.) + -ness. From late 14c. as "absence of duplicity; ignorance; absence of complexity."
simpleton (n.)
1640s, probably a jocular formation from simple and -ton, suffix extracted from surnames. Compare skimmington, personification of an ill-used spouse, c. 1600.
simplex (adj.)
"characterized by a single part," 1590s, from Latin simplex "single, simple, plain, unmixed, uncompounded," literally "onefold," from PIE compound of root *sem- (1) "one; as one, together with" + *plac- "-fold," from PIE root *plek- "to plait." The noun is attested from 1892, "simple uncompounded word."
simpliciter (adv.)
"not relatively; in the full sense of the word," a Latin adverb (from stem of simplex "simple;" see simplex) meaning, in classical Latin, "simply, plainly, directly, straightforwardly."
simplicity (n.)
late 14c., "singleness of nature, unity, indivisibility; immutability," from Old French simplicite (12c., Modern French simplicité), from Latin simplicitatem (nominative simplicitas) "state of being simple, frankness, openness, artlessness, candor, directness," from simplex (genitive simplicis) "simple" (see simplex). Sense of "ignorance" is from c. 1400; that of "simplicity of expression, plainness of style" is early 15c.

Middle English also had simplesse, from French, attested in English from mid-14c. in sense "humility, lack of pride," late 14c. as "wholeness, unity;" c. 1400 as "ignorance."
simplification (n.)
1680s, from Middle French simplification "act or process of simplifying," from simplifier (see simplify).
simplify (v.)
1650s, from French simplifier "to make simpler" (15c.), from Medieval Latin simplificare "to simplify," from Latin simplex "simple" (see simplex) + comb. form of facere "to make" (from PIE root *dhe- "to set, put"). Meaning "to make easier to do" is from 1759. Related: Simplified; simplifying.
simplism (n.)
"oversimplification," 1955, from simple (adj.) + -ism.
simplistic (adj.)
"simple, plain, not compound," 1844, from simple (adj.) + -istic. From 1867 as "over-simple, trying to explain too much by a single principle." Also (1860) "of or pertaining to simples" (herbs used in healing, medicine of one ingredient only; the notion being that each herb possesses a particular virtue, thus a "simple" remedy), from simplist "one who studies simples" (1590s; see simple (adj.)) + -ic.
simply (adv.)
late 13c., simpleliche; see simple + -ly (2). Purely intensive sense is attested from 1580s.
simulacrum (n.)
1590s, from Latin simulacrum "likeness, image, form, representation, portrait," dissimilated from *simulaclom, from simulare "to make like, imitate, copy, represent," from stem of similis "like, resembling, of the same kind" (see similar). The word was borrowed earlier as semulacre (late 14c.), via Old French simulacre.
simular (n.)
1520s, "one who simulates," irregularly formed (perhaps on the model of similar) from Latin simulare "to make like, imitate, copy, represent," from stem of similis "like, resembling, of the same kind" (see similar). As an adjective, "simulated," from 1610s.
simulate (v.)
1620s, "feign, pretend, assume falsely" (implied in simulated), back-formation from simulation or else from Latin simulatus, past participle of simulare "to make like, imitate, copy, represent," from stem of similis "like, resembling, of the same kind" (see similar). Meaning "to use a model to imitate certain conditions for purposes of study or training" is from 1947. Related: Simulating.
simulated (adj.)
1620s, "feigned," past participle adjective from simulate (v.). Meaning "imitative for purposes of experiment or training" is from 1966 (agent noun simulator in the related sense dates from 1947; also see simulation). In commercial jargon, "artificial, imitation" by 1942.
simulation (n.)
mid-14c., "a false show, false profession," from Old French simulation "pretence" and directly from Latin simulationem (nominative simulatio) "an imitating, feigning, false show, hypocrisy," noun of action from past participle stem of simulare "imitate," from stem of similis "like, resembling, of the same kind" (see similar). Meaning "a model or mock-up for purposes of experiment or training" is from 1954.
simulator (n.)
1835, of persons, from Latin simulator "a copier, feigner," agent noun from simulare "to make like, imitate, copy, represent," from stem of similis "like, resembling, of the same kind" (see similar). In reference to training devices for complex systems, from 1947 (flight simulator).
simulcast (v.)
"to broadcast simultaneously on radio and television," 1948, formed from simul(taneous) + (broad)cast. The noun is first recorded 1949, from the verb.