Skylab (n.)
name of a U.S. space program, first attested 1970, launched 1973, fell to earth 1979. From sky (n.) + lab (n.).
skylark (n.)
the common European lark, 1680s, from sky (n.) + lark (n.1). So called because it sings as it mounts toward the sky in flight.
skylark (v.)
"to frolic or play," 1809, originally nautical, in reference to "wanton play about the rigging, and tops," probably from skylark (n.), influenced by (or from) lark (n.2). Related: Skylarked; skylarking.
skylight (n.)
1670s, "light from the sky," from sky (n.) + light (n.). Meaning "small opening in a roof to admit light" is recorded from 1680s. Related: Sky-lit.
skyline (n.)
"horizon," 1824, from sky (n.) + line (n.).
skyrocket (n.)
1680s, type of firework, from sky (n.) + rocket (n.2). The verb, in the figurative sense of "to rise abruptly and rapidly" (often with suggestion of 'and then explode and vanish'") is attested from 1895.
skyscraper (n.)
very tall urban building, 1888, in a Chicago context, from sky (n.) + agent noun of scrape (v.). Used earlier for "ornament atop a building" (1883), "very tall man" (1857), "high-flying bird" (1840), "light sail at the top of a mast" (1794), and the name of a racehorse (1789). Compare cognate French gratte-ciel, from gratter "to scrape" + ciel "sky;" German Wolkenkratzer, from Wolke "cloud" + Kratzer "scraper."
cloud-cleaver, an imaginary sail jokingly assumed to be carried by Yankee ships. [W. Clark Russell, "Sailors' Word Book," 1883]
slab (n.)
late 13c., "large, flat mass," of unknown origin, possibly related to Old French escopel, escalpe "thin fragment of wood," which according to Klein is possibly a Gaulish word (compare Breton scolp, Welsh ysgolp "splinter, chip"). But OED rejects this on formal grounds. Meaning "rectangular block of pre-cast concrete used in building" is from 1927. Slab-sided is "having flat sides like slabs," hence "tall and lank" (1817, American English).
slack (n.2)
"coal dust," mid-15c., sleck, of uncertain origin, probably related to Middle Dutch slacke, Middle Low German slecke "slag, small pieces left after coal is screened," perhaps related to slagge "splinter flying off metal when it is struck" (see slag (n.)).
slack (adj.)
Old English slæc "remiss, lax, characterized by lack of energy, sluggish, indolent, languid; slow, gentle, easy," from Proto-Germanic *slakas (cognates: Old Saxon slak, Old Norse slakr, Old High German slah "slack," Middle Dutch lac "fault, lack"), from PIE root *(s)leg- "to be slack" (see lax).

Sense of "not tight" (in reference to things) is first recorded c.1300. As an adverb from late 14c. Slack-key (1975) translates Hawaiian ki ho'alu. Slack water (n.) "time when tide is not flowing" is from 1769. Slack-handed "remiss" is from 1670s. Slack-baked "baked imperfectly, half-baked" is from 1823; figuratively from 1840.
slack (n.1)
early 14c., "cessation" (of pain, grief, etc.), from slack (adj.). Meaning "a cessation of flow in a current or tide" is from 1756; that of "still stretch of a river" is from 1825. Meaning "loose part or end" (of a rope, sail, etc.) is from 1794; hence figurative senses in take up the slack (1930 figuratively) and slang cut (someone) some slack (1968). Meaning "quiet period, lull" is from 1851. Slacks "loose trousers" first recorded 1824, originally military.
slack (v.)
1510s, "to moderate, make slack," back-formed from slack (adj.) after the original verb veered into the specialized sense of slake. Meaning "be remiss, inactive or idle, fail to exert oneself" is attested from 1540s; current use is probably a re-coining from c.1904 (see slacker, and compare Old English slacful "lazy," sleacmodnes "laziness"). Related: Slacked; slacking.
slack-jawed (adj.)
1882, "over-talkative," from slack-jaw (n.) "impertinent language" (1797), from slack (adj.) + jaw (n.). Meaning "open-mouthed and speechless" from astonishment, stupidity, etc., is from 1905.
slacken (v.)
early 15c., from slack (adj.) + -en (1). Related: Slackened; slackening.
slacker (n.)
popularized 1994, but the meaning "person who shirks work" dates to 1897; agent noun from slack (v.). In early use also slackster (1901). Compare Old English sleacornes "laziness," which is not, however, an agent noun. Related: Slackerly; slackerish.
slackly (adv.)
Old English slæclice; see slack (adj.) + -ly (2).
slackness (n.)
Old English slæcnes "slowness, remissness, laziness;" see slack (adj.) + -ness.
slag (n.)
"refuse from smelting," 1550s, from Middle Low German slagge (German Schlacke) "splinter flying off when metal is struck," related to Old High German slahan "to strike, slay" (see slay (v.)).
slag (v.)
"denigrate," by 1971, from slag (n.) in a secondary sense of "worthless person" (1788). Related: Slagged; slagging.
slain (adj.)
early 13c., from Old English (ge)slegen, past participle of slean (see slay (v.)). The noun meaning "those who have been slain" is attested from mid-14c.
slake (v.)
late Old English sleacian, slacian "become slack or remiss; slacken an effort" (intransitive); "delay, retard" (transitive), from slæc "lax" (see slack (adj.)). Transitive sense of "make slack" is from late 12c. Sense of "allay, diminish in force, quench, extinguish" (in reference to thirst, hunger, desire, wrath, etc.) first recorded early 14c. via notion of "make slack or inactive." Related: Slaked; slaking.
slalom (n.)
1921, from Norwegian slalam "skiing race," literally "sloping track," from sla "slope" + lam "track" (related to Norwegian laan "a row of houses;" compare lane).
slam (n.1)
1670s, "a severe blow," probably from a Scandinavian source (compare Norwegian slamre, Swedish slemma "to slam, bang") of imitative origin. Meaning "a violent closing of a door" is from 1817. Meaning "an insult, put-down" is from 1884. Slam-bang recorded by 1806 (also slap-bang, 1785). Slam-dunk is from 1976; early use often in reference to Julius Erving. Slam-dance is attested by 1987 (slam by itself in this sense is recorded from 1983).
slam (n.2)
"a winning of all tricks in a card game," 1660s, earlier the name of a card game (also called ruff), 1620s, used especially in whist, of obscure origin. Grand slam in bridge first recorded 1892; earlier in related card games from 1814; figurative sense of "complete success" is attested from 1920; in baseball sense from 1935.
slam (v.)
1690s, "to beat, slap;" 1775 as "to shut with force," from slam (n.1). Meaning "throw or push with force" is from 1870. Meaning "say uncomplimentary things about" is from 1916. Related: Slammed; slamming.
slammer (n.)
"jail, prison," 1952, perhaps from earlier U.S. slang sense of "door" (by 1943), agent noun from slam (v.). As "one who slams," from 1892.
slander (n.)
late 13c., "state of impaired reputation, disgrace or dishonor;" c.1300, "a false tale; the fabrication and dissemination of false tales," from Anglo-French esclaundre, Old French esclandre "scandalous statement," alteration ("with interloping l" [Century Dictionary]) of escandle, escandre "scandal," from Latin scandalum "cause of offense, stumbling block, temptation" (see scandal). From late 14c. as "bad situation, evil action; a person causing such a state of affairs."
slander (v.)
c.1300, from Anglo-French esclaundrer, Old French esclandrer, from esclandre (see slander (n.)). Related: Slandered; slandering; slanderer.
slanderous (adj.)
early 15c., from slander + -ous. Related: Slanderously; slanderousness.
slang (n.)
1756, "special vocabulary of tramps or thieves," later "jargon of a particular profession" (1801), of uncertain origin, the usual guess being that it is from a Scandinavian source, such as Norwegian slengenamn "nickname," slengja kjeften "to abuse with words," literally "to sling the jaw," related to Old Norse slyngva "to sling." But OED, while admitting "some approximation in sense," discounts this connection based on "date and early associations." Liberman also denies it, as well as any connection with French langue (or language or lingo). Rather, he derives it elaborately from an old slang word meaning "narrow piece of land," itself of obscure origin. Century Dictionary says "there is no evidence to establish a Gipsy origin." Sense of "very informal language characterized by vividness and novelty" first recorded 1818.
[S]lang is a conscious offence against some conventional standard of propriety. A mere vulgarism is not slang, except when it is purposely adopted, and acquires an artificial currency, among some class of persons to whom it is not native. The other distinctive feature of slang is that it is neither part of the ordinary language, nor an attempt to supply its deficiencies. The slang word is a deliberate substitute for a word of the vernacular, just as the characters of a cipher are substitutes for the letters of the alphabet, or as a nickname is a substitute for a personal name. [Henry Bradley, from "Slang," in "Encyclopedia Britannica," 11th ed.]
A word that ought to have survived is slangwhanger (1807, American English) "noisy or abusive talker or writer."
slangy (adj.)
1822, from slang (n.) + -y (2). Related: Slanginess. Slangular (1852) also was tried.
slant (n.)
1650s, "an oblique direction or plane" (originally of landforms), from slant (v.). Meaning "a way of regarding something" is from 1905. Derogatory slang sense of "a slant-eyed Asian person" is recorded from 1943, from earlier slant-eyes (1929).
slant (v.)
1520s, "to strike obliquely" (against something), alteration of slenten "slip sideways" (c.1300), perhaps via a Scandinavian source (compare Swedish slinta "to slip," Norwegian slenta "to fall on one side"), from Proto-Germanic *slintanan. Intransitive sense of "to slope, to lie obliquely" is first recorded 1690s; transitive sense of "to give a sloping direction to" is from 1805. Related: Slanted; slanting. As an adverb from late 15c.; as an adjective from 1610s. Slant rhyme attested from 1944.
slantways (adv.)
1826, from slant (n.) + way (n.) + adverbial genitive -s.
slap (v.)
late 15c., "strike with the open hand," from slap (n.). As an adverb, 1670s, "suddenly;" 1829, "directly." Related: Slapped; slapping.
slap (n.)
mid-15c., probably of imitative origin, similar to Low German slappe, German Schlappe. Figurative meaning "insult, reprimand" is attested from 1736. Slap-happy (1936) originally meant "punch-drunk." Slap on the wrist "very mild punishment" dates from 1914.
slapdash (adv.)
1670s, from slap (v.) + dash (v.). As an adjective, "dashing, offhand, careless," from 1792. As a noun, "rough-coat, coarse plaster," from 1796.
slapper (n.)
"large or impressive person or thing," 1781, agent noun from slap (v.). Also see whopper.
slapshot (n.)
in ice hockey, 1942, from slap (v.) + shot (n.).
slapstick (n.)
also slap-stick, originally (1896) a device consisting of two sticks fastened together so as to slap loudly when a clown or actor hits somebody with it, or to make a sound-effect offstage; from slap and stick (n.). As an adjective by 1906. Meaning "farcical physical comedy, horseplay" (1916) is short for slapstick comedy or humor.
slash (v.)
1540s, "to cut with a stroke of a blade or whip;" 1650s, "to strike violently," perhaps from Middle French esclachier "to break," variant of esclater "to break, splinter" (see slat). Meaning "to clear land" (of trees) is from 1821, American English. In reference to prices, it is attested from 1906. Related: Slashed; slashing. Slash-and-burn for a method of clearing forest for cultivation is from 1919.
slash (n.)
"a cutting stroke with a weapon," 1570s, from slash (v.); sense of "slit in a garment" is from 1610s; that of "open tract in a forest" is first attested 1825, American English. As a punctuation mark in writing or printing, it is recorded from 1961.
slasher (n.)
1550s, "a bully, a fighter;" 1815, "weapon for slashing," agent noun from slash (v.). As "violent movie" by 1978.
slat (n.)
late 14c., earlier sclat (c.1300), "a roofing slate, a thin, flat stone," from Old French esclat "split piece, chip, splinter" (Modern French éclat), back-formation from esclater "to break, splinter, burst," probably from Frankish *slaitan "to tear, slit" or some other Germanic source (compare Old High German slizan, Old English slitan; see slit (v.)). Meaning "long, thin, narrow piece of wood or metal" attested from 1764.
slate (n.)
mid-14c., from Old French esclate, fem. of esclat "split piece, splinter" (Modern French éclat; see slat), so called because the rock splits easily into thin plates. As an adjective, 1510s. As a color, first recorded 1813. Sense of "a writing tablet" (made of slate), first recorded late 14c., led to that of "list of preliminary candidates prepared by party managers," first recorded 1842, from notion of being easily altered or erased. Clean slate (1856) is an image from customer accounts chalked up in a tavern.
slate (v.)
1520s, "to cover with slates" (earlier sclatten, late 15c.), from slate (n.). Meaning "propose, schedule" is from 1883; earlier "to nominate" (1804); the notion is of writing on a slate board. Related: Slated; slating.
slater (n.)
"one who makes or lays slates," c.1400 (mid-13c. as a surname), agent noun from slate.
slather (v.)
"spread liberally," 1847, of uncertain origin. Early 19c. local glossaries from western England have the word with a sense "to slip or slide."
Slather on the manure on all the hoed crops, if you have it; if not buy of your improvident neighbor. ["Genesee Farmer," June 1847]
Sometimes said to be from a dialectal noun meaning "large amount" (usually as plural, slathers), but this is first attested 1855. Related: Slathered; slathering.
slattern (n.)
1630s, "a woman negligent or disordered in her dress or household," of uncertain origin, probably related to Low German Slattje, Dutch slodder, dialectal Swedish slata "slut" (in the older, non-sexual sense; compare slut). Compare dialectal English verb slatter "to spill or splash awkwardly, to waste," used of women or girls considered untidy or slovenly.
slatternly (adj.)
1670s, from slattern + -ly (1).