Online Etymology Dictionary

serenade (n.): 1640s, "musical performance at night in open air" (especially one given by a lover under the window of his lady), from French sérénade (16c.), from Italian serenata "an evening song," literally "calm sky," from sereno "the open air," noun use of sereno "clear, calm," from Latin serenus "peaceful, calm, serene." Sense influenced by Italian sera "evening," from Latin sera, fem. of serus "late." Meaning "piece of music suitable for a serenade" is attested from 1728.
serenade (v.): 1660s, from serenade (n.). Related: Serenaded; serenading.
serendipitous (adj.): 1914; see serendipity + -ous. Related: Serendipitously.
serendipity (n.): 1754 (but rare before 20c.), coined by Horace Walpole (1717-92) in a letter to Horace Mann (dated Jan. 28); he said he formed it from the Persian fairy tale "The Three Princes of Serendip," whose heroes "were always making discoveries, by accidents and sagacity, of things they were not in quest of." The name is from Serendip, an old name for Ceylon (modern Sri Lanka), from Arabic Sarandib, from Sanskrit Simhaladvipa "Dwelling-Place-of-Lions Island."
serene (adj.): mid-15c., "clear, calm," from Latin serenus "peaceful, calm, clear" (of weather), figuratively "cheerful, glad, tranquil," of uncertain origin; perhaps from a suffixed variant of PIE *ksero- "dry," source of Greek xeros "dry" (see xerasia). In English, applied to persons since 1630s. Related: Serenely.
serenity (n.): 1530s, of weather, 1590s, of persons, from Middle French sérénité, from Latin serenitatem (nominative serenitas) "clearness, serenity," from serenus (see serene). Earliest use (mid-15c.) was as a title of honor for kings, probably from the similar use of Latin serenitas, applied to Roman emperors, later popes.
serf (n.): late 15c., "servant, serving-man, slave," from Old French serf "vassal, servant, slave" (12c.), from Latin servum (nominative servus) "slave" (see serve). Fallen from use in original sense by 18c. Meaning "lowest class of cultivators of the soil in continental European countries" is from 1610s. Use by modern writers with reference to medieval Europeans first recorded 1761 (contemporary Anglo-Latin records used nativus, villanus, or servus).
serfdom (n.): 1850, from serf + -dom. Earlier in the same sense was serfage (1775).
serge (n.): type of strong, twilled fabric used for coats, etc., late 14c., from Old French serge (12c.), from Vulgar Latin *sarica, in Medieval Latin "cloth of wool mixed with silk or linen," from Latin serica (vestis) "silken (garment)," from serica, from Greek serike, fem. of serikos "silken" (see silk). The French word is the source of German sarsche, Danish sarge, etc. Also as a verb. Related: Serger.
sergeant (n.): c. 1200, "servant," from Old French sergent, serjant "(domestic) servant, valet; court official; soldier," from Medieval Latin servientum (nominative serviens) "servant, vassal, soldier" (in Late Latin "public official"), from Latin servientem "serving," present participle of servire "to serve" (see serve (v.)); cognate with Spanish sirviente, Italian servente; a twin of servant, and 16c. writers sometimes use the two words interchangeably.

Specific sense of "military servant" is attested from late 13c.; that of "officer whose duty is to enforce judgments of a tribunal or legislative body" is from c. 1300 (sergeant at arms is attested from late 14c.). Meaning "non-commissioned military officer" first recorded 1540s. Originally a much more important rank than presently. As a police rank, in Great Britain from 1839.

Middle English alternative spelling serjeant (from Old French) was retained in Britain in special use as title of a superior order of barristers (c. 1300, from legal Latin serviens ad legem, "one who serves (the king) in matters of law"), from which Common Law judges were chosen; also used of certain other officers of the royal household. sergeant-major is from 1570s. The sergeant-fish (1871) so-called for lateral markings resembling a sergeant's stripes. Related: Sergeancy.
Sergius: masc. proper name, from Latin, of Etruscan origin.
serial (adj.): "coming in regular succession," 1840, from series + -al (1); popularized in reference to Dickens' novels, published one part at a time in periodicals (as opposed to all at once in a book). Found to be a useful word and given wide application. Serial number, indicating position in a series, first recorded 1866, originally of papers, packages, etc.; of soldiers from 1918. Serial killer is first attested 1981 (in relation to John Wayne Gacy and Ted Bundy), though serial had been used in connection with murders since the early 1960s. Related: Serially.
serial (n.): 1846, from serial (adj.).
serialization (n.): 1856, noun of action from serialize.
serialize (v.): 1852 (implied in serialized), from serial + -ize. Related: Serializing.
seriatim: 1670s (earlier seratim, c. 1500), "one after another," from Medieval Latin seriatim, from Latin series (see series).
seriation (n.): "the forming of an orderly sequence," 1650s; see series + -ation.
sericulture (n.): "breeding, rearing and treatment of silkworms, 1839, from French sériciculture (19c.), from Latin sericum (nominative serica) "silk" (see serge) + cultura (see culture (n.)).
series (n.): 1610s, "a number or set of things of one kind arranged in a line," from Latin series "row, chain, series, sequence, succession," from serere "to join, link, bind together, arrange, attach, put; join in speech, discuss," from PIE root *ser- (3) "to line up, join" (source also of Sanskrit sarat- "thread," Greek eirein "to fasten together in rows," Gothic sarwa (plural) "armor, arms," Old Norse sörve "necklace of stringed pearls," Old Irish sernaid "he joins together," Welsh ystret "row").

Meaning "set of printed works published consecutively" is from 1711. Meaning "set of radio or television programs with the same characters and themes" is attested from 1949. Baseball sense "set of games on consecutive days between the same teams" is from 1862.
serif (n.): in typography, 1841, earlier ceref (1827); see sans-serif.
serine (n.): type of amino acid, 1880, from German serin (1865), from Latin sericum "silk" (see serge), with chemical suffix -ine (2).
seriocomic (adj.): also serio-comic, 1749 (implied in seriocomical), a blend of serious + comic.
serious (adj.): mid-15c., "expressing earnest purpose or thought" (of persons), from Middle French sérieux "grave, earnest" (14c.), from Late Latin seriosus, from Latin serius "weighty, important, grave," probably from a PIE root *swer- (4) "heavy" (source also of Lithuanian sveriu "to weigh, lift," svarus "heavy, weighty;" Old English swær "heavy," German schwer "heavy," Gothic swers "honored, esteemed," literally "weighty"). As opposite of jesting, from 1712; as opposite of light (of music, theater, etc.), from 1762. Meaning "attended with danger" is from 1800.
seriously (adv.): c. 1500, from serious + -ly (2). To take (something) seriously is from 1782.
seriousness (n.): 1520s, from serious + -ness.
sermocination (n.): 1510s, "a talk," from Latin sermonationem (nominative sermonatio), noun of action from past participle stem of sermonari "talk, discourse, harangue," from sermo (see sermon). From 1753 in rhetoric, "a form of prosopopoeia in which the speaker, having addressed a real or imaginary hearer with a remark or especially a question, immediately answers for the hearer." Related: Sermocinator, agent noun; sermocinatrix "a female talker" (1620s).
sermon (n.): c. 1200, sarmun, "a discourse upon a text of scripture; what is preached," from Anglo-French sermun, Old French sermon "speech, words, discourse; church sermon, homily" (10c.), from Latin sermonem (nominative sermo) "continued speech, conversation; common talk, rumor; learned talk, discourse; manner of speaking, literary style," originally "a stringing together of words," from PIE *ser-mo-, suffixed form of root *ser- (3) "to line up, join" (see series).

Main modern sense in English and French is elliptical for Latin sermo religiosus. In transferred (non-religious) use from 1590s. The Sermon on the Mount is in 5,6,7 Matt. and 6 Luke. Related: Sermonic; sermonical; sermonish.
sermonette (n.): 1814, diminutive from sermon + -ette. Poe used sermonoid (1849); sermuncle (1886) also has been tried. English writers have turned to the Italian double diminutive sermonettino (1818) to describe notably trifling efforts.
sermonize (v.): 1630s, from Medieval Latin sermonizari, from Latin sermo (see sermon). "Chiefly depreciatory" [OED]. Related: Sermonizing.
serology (n.): 1907, from sero-, comb. form of serum, + -ology. Related: Serological; serologist.
serotine (adj.): "late," 1590s, from French sérotine, from Latin serotinus "that which comes late; that which happens in the evening," from sero, adverb of serus "late" (see soiree). Also as a noun, a type of small, brown bat, from 1771. Related: serotinous, in botany (1880) "appearing later in the season than usual."
serotonin (n.): neurotransmitting chemical, 1948, coined from sero-, comb. form of serum (q.v.) + ton(ic) + chemical suffix -in (2).
serous (adj.): early 15c., "watery," later "of or pertaining to serum" (16c.), from French séreux (16c.) and directly from Latin serosus, from serum "watery fluid, whey" (see serum). Related: Serosity.
serpent (n.): c. 1300, "limbless reptile," also the tempter in Gen. iii:1-5, from Old French serpent, sarpent "snake, serpent" (12c.), from Latin serpentem (nominative serpens) "snake; creeping thing," also the name of a constellation, from present participle of serpere "to creep," from PIE *serp- "to crawl, creep" (source also of Sanskrit sarpati "creeps," sarpah "serpent;" Greek herpein "to creep," herpeton "serpent;" Albanian garper "serpent").

Used figuratively of things spiral or regularly sinuous, such as a type of musical instrument (1730). Serpent's tongue as figurative of venomous or stinging speech is from mistaken medieval notion that the serpent's tongue was its "sting." Serpent's tongue also was a name given to fossil shark's teeth (c. 1600).
serpentine (n.): c. 1400, "plant reputed to contain antivenom," from Old French serpentin name of a precious stone, noun use of adjective meaning "of a snake, snake-like; sly, deceptive," from Late Latin serpentius "of a serpent," from Latin serpentem (nominative serpens) "snake" (see serpent). As the name of a greenish igneous rock consisting mainly of hydrous magnesium silicate, attested from early 15c.
serpentine (adj.): "twisting, winding," 1610s; see serpent + -ine (1). An earlier adjective meaning "having the evil qualities of a serpent" is recorded from late 14c., from the French source of serpentine (n.). The winding lake of that name in Hyde Park, London, was constructed in 1730.
serrate (adj.): "notched," 1660s, from Latin serratus "sawlike, notched like a saw," from serra "a saw," of unknown origin. Related: Serrated; serrating.
serrated (adj.): 1703, past participle adjective based on Latin serratus (see serrate (adj.)). Serrating "sawing" attested from 1590s, but serrate as a transitive verb not attested before 1750 according to OED.
serration (n.): "condition of being serrated," 1808, noun of state from serrate (adj.).
serried (adj.): "pressed close together," 1667 (in "Paradise Lost"), probably a past participle adjective from serry "to press close together" (1580s), a military term, from Middle French serre "close, compact" (12c.), past participle of serrer "press close, fasten," from Vulgar Latin *serrare "to bolt, lock up," from Latin serare, from sera "a bolt, bar, cross-bar," perhaps from PIE *ser- (3) "to line up" (see series). Modern use is due to the popularity of Scott, who used it with phalanx.
serum (n.): 1670s, "watery animal fluid," from Latin serum "watery fluid, whey," from PIE root *ser- (2) "to run, flow" (source also of Greek oros "whey;" Sanskrit sarah "flowing," sarit "brook, river"). First applied 1893 to blood serum used in medical treatments.
serval (n.): African wild cat, 1771, from Modern Latin serval, French serval (Buffon, 1765), from Portuguese (lobo) cerval "lynx," from Latin lupus cervarius (source of French loup cervier) "lynx," literally "wolf that hunts the stag," from cervarius "pertaining to a stag," from cervus "stag," from PIE *ker-wo- "having horns," suffixed form of root *ker- (1) "horn, head" (see horn (n.)).
servant (n.): c. 1200, "personal or domestic attendant," from Old French servant "servant; foot-soldier," noun use of servant "serving, waiting," present participle of servir "to attend, wait upon" (see serve (v.)).

Meaning "professed lover, one devoted to the service of a lady" is from mid-14c. In North American colonies and U.S., the usual designation for "slave" 17c.-18c. (in 14c.-15c. and later in Biblical translations the word often was used to render Latin servus, Greek doulos "slave"). Public servant is attested from 1670s.
serve (v.): late 12c., "to render habitual obedience to," also "minister, give aid, give help," from Old French servir "to do duty toward, show devotion to; set table, serve at table; offer, provide with," from Latin servire "be a servant, be in service, be enslaved;" figuratively "be devoted; be governed by; comply with; conform; flatter," originally "be a slave," related to servus "slave," perhaps from Etruscan (compare Etruscan proper names Servi, Serve, Latinized as Servius).

By c. 1200 also as "to be in the service of, perform a service for; attend upon, be personal servant to; be a slave; owe allegiance to; officiate at Mass or other religious rites;" from early 13c. as "set food at table;" mid-14c. as "to wait on (customers)." From late 14c. as "treat (someone or something) in some fashion." To serve (someone) right "to treat as he deserves" is recorded from 1580s.
He no schuld neuer wond
To seruen him fro fot to hond
["Amis and Amiloun," c. 1330]
Sense of "be useful, be beneficial, be suitable for a purpose or function" is from early 14c.; that of "take the place or meet the needs of, be equal to the task" is from late 14c.; that of "suffice" is from mid-15c. Meaning "render active military service" is from 1510s. Sporting sense, in tennis, badminton, etc., first recorded 1580s. Legal sense "present" (a writ, warrant,etc.), "give legal notice of" is from early 15c.
serve (n.): 1680s, in sports (tennis, etc.), from serve (v.).
served (adj.): "found guilty, convicted; ordered to be punished or transported; beaten," 1811, slang past participle adjective from serve (v.).
server (n.): late 14c., agent noun from serve (v.). Computer sense by 1992.
servery (n.): 1893, from serve + -ery.
Servian: 1754 (n.), 1723 (adj.), from Medieval Latin Servia, from Serb Serb (see Serb).
service (v.): 1893, "to provide with service," from service (n.1). Meaning "perform work on" first recorded 1926. Related: Serviced; servicing.