Online Etymology Dictionary

self-righteous (adj.): 1680s, from self- + righteous. Related: Self-righteously; self-righteousness.
self-sacrifice (n.): 1805, from self- + sacrifice (n.). Adjective self-sacrific'd attested from 1711. Related: self-sacrificing.
self-satisfaction (n.): 1739, from self- + satisfaction. Related: Self-satisfied (1734).
self-seeking (n.): "a seeking after one's own benefit (before those of others)," 1580s, from self + seeking, verbal noun from seek. As an adjective, from 1620s.
self-service (adj.): 1919, in reference to grocery stores, from self- + service (n.1).
self-serving (adj.): also self serving, 1827, from self- + serving, present participle adjective from serve (v.).
self-starter (n.): 1894, of engines, 1960, of persons (especially workers), from self- + starter. Self-starting (adj.), of motors, is attested from 1866.
self-styled (adj.): 1833, from self- + past tense of style (v.).
self-sufficiency (n.): 1620s, originally an attribute of God (translating Greek autakreia), from self- + sufficiency. Of mortals, self-sufficient "able to supply one's own needs" is recorded from 1580s.
self-sufficient (adj.): "able to supply one's own needs," 1580s, from self- + sufficient. Related: Self-sufficiently.
self-sustaining (adj.): 1806, from self- + present participle of sustain (v.).
self-willed (adj.): late 15c., from self- + willed (see will (v.1)). In Old English, selfwill meant "free will."
self-worth (n.): also self worth, 1650s, from self- + worth (n.).
selfie (n.): "photograph taken by pointing the camera at oneself," by 2005, said to be in use by 2002, from self + -ie.
selfish (adj.): 1630s, from self- + -ish. Said in Hacket's life of Archbishop Williams (1693) to have been coined by Presbyterians. In the 17c., synonyms included self-seeking (1620s), self-ended and self-ful.
Let us understand what our own selfish genes are up to, because we may then at least have the chance to upset their designs. [Richard Dawkins, "The Selfish Gene," 1976]
Related: Selfishly; selfishness. Similar formations in German selbstisch, Swedish sjelfvisk, Danish selvisk.
selfless (adj.): "devoted to others' welfare or interest and not one's own," 1825, from self + -less. First attested in Coleridge. Related: Selflessly; selflessness.
selfsame: "identical," early 15c., from self + same. Written as two words until c. 1600.
Selina: fem. proper name, nativized form of French Céline, from Latin caelina "heavenly," from caelum (see celestial).
Seljuk: Turkish dynasty of 11c.-13c., c. 1600 (Selzuccian), from Turkish seljuq, name of reputed ancestor of the dynasty.
sell (v.): Old English sellan "to give, furnish, supply, lend; surrender, give up; deliver to; promise," from Proto-Germanic *saljan "offer up, deliver" (source also of Old Norse selja "to hand over, deliver, sell;" Old Frisian sella, Old High German sellen "to give, hand over, sell;" Gothic saljan "to offer a sacrifice"), ultimately from PIE root *sel- (3) "to take, grasp."

Meaning "to give up for money" had emerged by c. 1000, but in Chaucer selle still can mean "to give." Students of Old English learn early that the word that looks like sell usually means "give." An Old English word for "to sell" was bebycgan, from bycgan "to buy."

Slang meaning "to swindle" is from 1590s. The noun phrase hard sell is recorded from 1952. To sell one's soul is from c. 1570. Sell-by date is from 1972. To sell like hot cakes is from 1839. Selling-point attested from 1959.

To sell (someone) down the river figuratively is by 1927, probably from or with recollection of slavery days, on notion of sale from the Upper South to the cotton plantations of the Deep South (attested in this literal sense since 1851).
seller (n.): c. 1200, agent noun from sell (v.).
Sellotape (n.): 1949, proprietary name, Great Britain.
sellout (n.): also sell-out, "corrupt bargain," 1862 (in Mary Chesnut's diary), from the verbal phrase (at that time often meaning "dispose of one's interests" in a company, etc.), from sell (v.) + out (adv.). Meaning "event for which all tickets have been sold" is attested from 1923. The verbal phrase sell out "prostitute one's ideals or talents" is attested from 1888.
seltzer: 1741, from German Selterser (Wasser), a kind of mineral water, literally "of Selters," village near Weisbaden in Hesse-Nassau, where the mineral water is found.
selvage (n.): mid-15c., "edge of web or cloth so finished as to prevent raveling," apparently literally "its own edge," a corruption of self + edge (n.); on analogy of Middle Flemish selvegge (compare also Low German sulfegge; Dutch zelfkant, from kant "border;" Middle High German selbende, German Selbend, literally "self-end").
semantic (adj.): 1894, from French sémantique, applied by Michel Bréal (1883) to the psychology of language, from Greek semantikos "significant," from semainein "to show by sign, signify, point out, indicate by a sign," from sema "sign, mark, token; omen, portent; constellation; grave" (Doric sama), from PIE root *dheie- "to see, look" (source also of Sanskrit dhyati "he meditates;" see zen).
semantics (n.): "science of meaning in language," 1893, from French sémantique (1883); see semantic (also see -ics). Replaced semasiology (1847), from German Semasiologie (1829), from Greek semasia "signification, meaning."
semaphore (n.): "apparatus for signaling," 1816, probably via French sémaphore, literally "a bearer of signals," ultimately from Greek sema "sign, signal" (see semantic) + phoros "bearer," from pherein "to carry" (see infer). Related: Semaphoric (1808).
sematic (adj.): "significant, indicative," 1890, from Greek semat-, comb. form of sema (genitive sematos) "sign" (see semantic) + -ic. Used especially in biology, in reference to "warning" colors, etc.
semblable (adj.): "resembling," late 14c., from Old French semblable (12c.), from sembler "to be like" (see semblance).
semblance (n.): c. 1300, "fact of appearing to view," from Old French semblance, from semblant "likeness, appearance," present participle of sembler "to seem, appear," from Latin simulare "to resemble, imitate," from similis "like" (see similar (adj.)). Meaning "person's appearance or demeanor" is attested from c. 1400; that of "false, assumed or deceiving appearance" is from 1590s. Meaning "person or thing that resembles another" is attested from 1510s.
seme (n.): in linguistics, 1866, from Greek sema "sign" (see semantic). Compare pheme, etc.
seme (adj.): "covered with a small, constantly repeating pattern," 1560s, from Middle French semée "strewn, sprinkled," past participle of semer, from Latin seminare "to sow," from semen (genitive seminis) "seed" (see semen).
Semele: daughter of Cadmus and mother of Dionysus, from Latin, from Greek Semele, a Thraco-Phrygian earth goddess, from Phrygian Zemele "mother of the earth," probably cognate with Old Church Slavonic zemlja "earth," Latin humus "earth, ground, soil" (see chthonic).
semen (n.): late 14c., from Latin semen "seed of plants, animals, or men; race, inborn characteristic; posterity, progeny, offspring," figuratively "origin, essence, principle, cause," from PIE *semen- "seed," suffixed form of root *se- (1) "to sow" (source also of Latin serere "to sow," Old Prussian semen "seed," Lithuanian semens "seed of flax," Old Church Slavonic seme, Old High German samo "seed," German Same; see sow (v.)).
semester (n.): 1827, from German Semester "half-year course in a university," from Latin semestris, in cursus semestris "course of six months," from semestris, semenstris "of six months, lasting six months, half-yearly, semi-annual," from sex "six" (see six) + mensis "month" (see moon (n.)). Related: Semestral; semestrial.
semi-: before vowels sem-, word-forming element meaning "half, part, partly; partial, imperfect; twice," from Latin semi- "half," from PIE *semi- "half" (source also of Sanskrit sami "half," Greek hemi- "half," Old English sam-, Gothic sami- "half").

Old English cognate sam- was used in such compounds as samhal "poor health," literally "half-whole;" samsoden "half-cooked," figuratively "stupid" (compare half-baked); samcucu "half-dead," literally "half-alive;" and the last survivor of the group, sandblind "dim-sighted" (q.v.). Common in Latin (as in semi-gravis "half-drunk," semi-hora "half hour," semi-mortuus "half-dead," semi-nudus "half-naked," semi-vir "half-man, hermaphrodite"). The Latin-derived form in English has been active in forming native words since 15c.
semi-annual (adj.): also semiannual, 1775, from semi- + annual. Related: Semiannually.
semi-arid (adj.): also semiarid, 1886, from semi- + arid.
semi-automatic (adj.): 1853, from semi- + automatic (adj.). In reference to firearms, 1889.
semi-demi-: word-forming element meaning "sixty-fourth part," 1660s; see semi- + demi-.
semi-detached (adj.): in reference to houses, 1845, from semi- + past participle of detach (v.).
The "Detached House" bears its peculiar characteristic on its front; it stands alone, and nothing more can be said about it; but with the "semi-detached house" there is a subtle mystery, much to be marvelled at. Semi-detached! Have the party-walls between two houses shrunk, or is there a bridge connecting the two, as in Mr. Beckford's house in Landsdown Crescent, Bath? A semi-detached house may be a house with a field on one side and a bone-boiling factory on the other. Semi-detached may mean half-tumbling to pieces. I must inquire into it. ["Houses to Let," in "Household Words," March 20, 1852]
semi-monthly (adj.): also semimonthly, 1809, from semi- + monthly.
semi-official (adj.): 1798, from semi- + official (adj.). Related: Semi-officially.
semi-permeable (adj.): 1873, from semi- + permeable. Translating German halbdurchlässig.
semi-professional (adj.): 1824, from semi- + professional (adj.). As a noun from 1843. Related: Semi-professionally.
semi-solid (adj.): 1803, from semi- + solid (adj.).
semi-trailer (n.): also semitrailer, 1910 in reference to motor vehicles (late 19c. in botany), from semi- + trailer.Short form semi is attested from 1942.
semi-weekly (adj.): also semiweekly, "occurring twice a week," 1791, from semi- + weekly.
semicircle (n.): 1520s, from semi- + circle (n.) or else from Latin semicirculus.