Online Etymology Dictionary

Laertes: king of Ithaca, father of Odysseus, his name is Greek, literally "gatherer of the people," or "urging the men," from laos "people" (see lay (adj.)) + eirein "to fasten together" (see series (n.)) or eirein "to speak, say" (see verb).
lag (v.): "move slowly, fail to keep pace," 1520s, earlier as a noun meaning "last person" (1510s), later also as an adjective, "slow, tardy, coming behind" (1550s, as in lag-mon "last man"). All are of uncertain relationship and origin, possibly from a Scandinavian source (compare Norwegian lagga "go slowly"), or some dialectal version of last, lack, or delay. Related: Lag; lagging.
lag (n.): in the mechanical sense "retardation of movement," 1855, from lag (v.). Also noted in Farmer & Henley as American theatrical slang for "a wait," with an attestation from 1847. First record of lag time is from 1951.
lager (n.): 1858, American English, short for lager beer (1845), from German Lagerbier "beer brewed for keeping" some months before being drunk, from Lager "storehouse" (see lair) + Bier "beer."
laggard (adj.): 1702, "slow, sluggish," from lag (v.) + -ard. From 1757 as a noun, "one who lags, a shirker, loiterer." Related: Laggardly.
lagniappe (n.): also lagnappe, "dividend, something extra, present or extra item given by a dealer to a customer to encourage patronage," 1849, from New Orleans creole, of unknown origin though much speculated upon. Originally a bit of something given by New Orleans shopkeepers to customers. Said to be from American Spanish la ñapa "the gift." Klein says this is in turn from Quechua yapa "something added, gift."
We picked up one excellent word -- a word worth travelling to New Orleans to get; a nice, limber, expressive, handy word -- 'lagniappe.' They pronounce it lanny-yap. It is Spanish -- so they said. [Mark Twain, "Life on the Mississippi," 1883]
lagoon (n.): 1670s, lagune, earlier laguna (1610s), "area of marsh or shallow, brackish water beside a sea but separated from it by dunes," from French lagune or directly from Italian laguna "pond, lake," from Latin lacuna "pond, hole," from lacus "pond" (see lake (n.1)). Originally in reference to the region of Venice. The word was applied 1769 (by Capt. Cook) to the lake-like stretch of water enclosed in a South Seas atoll. Also see -oon. Related: Lagoonal.
In regions where Spanish is or formerly was the current language, the word lagoon is likely to be used with more latitude of meaning, since in the Spanish laguna is applied to ordinary lakes, to the bottoms of deep bays, especially when these are more or less closed in by a narrowing of the coast-lines, so as to give rise to lake-like areas, and also to shallow, swampy, or almost dried-up lakes inland as well as near the coast. [Century Dictionary]
lai (n.): type of medieval poem; see lay (n.).
laic (adj.): 1560s, "belonging to the people" (as distinguished from the clergy and the professionals), from French laïque (16c.), from Late Latin laicus, from Greek laikos "of or belonging to the people," from laos "people" (see lay (adj.)).
laicize (v.): 1856; see laic + -ize. Related: Laicized; laicizing.
laid (adj.): "put or set down," 17c. adjectival use of past tense and past participle of lay (v.). Laid-up "injured, sick, incapacitated," originally was a nautical term (1769) describing a ship moored in harbor. Laid off "temporarily unemployed" is from 1916 (see layoff). Slang get laid "have sex" (with someone) attested from 1952, American English. Laid-back (adj.) "relaxed" is first attested 1973, perhaps in reference to the posture of highway motorcyclists.
laidly (adj.): also laithly, c. 1300, Scottish and northern English variant of loathly "hideous, repulsive" (see loath). A word preserved in old ballads; in modern use consciously archaic.
lain: past participle of lie (v.2).
lair (n.): Old English leger "act or place of lying down; bed, couch; illness; the grave," from Proto-Germanic *legraz (source also of Old Norse legr "the grave," also "nuptials" (both "a lying down"); Old Frisian leger "situation," Old Saxon legar "bed," Middle Dutch legher "act or place of lying down," Dutch leger "bed, camp," Old High German legar "bed, a lying down," German Lager "bed, lair, camp, storehouse," Gothic ligrs "place of lying"), from PIE *legh- "to lie, lay" (see lie (v.2)). Meaning "animal's den" is from early 15c. Essentially the same word as layer (n.), but more ancient and differentiated in sense.
laird (n.): "landed proprietor or hereditary estate-holder in Scotland," mid-15c. (mid-13c. as a surname), Scottish and northern England dialectal variant of lord, from Middle English laverd (see lord (n.)). Related: Lairdship.
laissez-faire: also laissez faire, 1822, French, literally "let (people) do (as they think best)," from laissez, second person plural imperative of laisser "to let, to leave" (10c., from Latin laxare, from laxus "loose;" see lax) + faire "to do" (from Latin facere; see factitious). From the phrase laissez faire et laissez passer, motto of certain 18c. French economists, chosen to express the ideal of government non-interference in business and industry. Compare laisser-faire "a letting alone," taken to mean "non-interference with individual freedom of action" as a policy in government and political economy.
laity (n.): "body of people not in religious orders," early 15c., from Anglo-French laite, from lay (adj.) + -ity.
lake (n.1): "body of water surrounded by land and filling a depression or basin," early 12c., from Old French lack (12c., Modern French lac) and directly from Latin lacus "pond, pool, lake," also "basin, tank, reservoir" (related to lacuna "hole, pit"), from PIE *laku- "body of water, lake, sea" (source also of Greek lakkos "pit, tank, pond," Old Church Slavonic loky "pool, puddle, cistern," Old Irish loch "lake, pond"). The common notion is "basin."

There was a Germanic form of the PIE root which yielded Old Norse lögr "sea flood, water," Old English lacu "stream, pool, pond," lagu "sea flood, water, extent of the sea," leccan "to moisten" (see leak (v.)). In Middle English, lake, as a descendant of the Old English word, also could mean "stream; river gully; ditch; marsh; grave; pit of hell," and this might have influenced the form of the borrowed word.
lake (n.2): "deep red coloring matter," 1610s, from French laque (15c., see lac), from which it was obtained.
lake (v.): "to play, sport," Old English lacan (see lark (n.2)).
laker (n.): a word used of people or things associated in various ways with a lake or lakes, including tourists to the English Lake country (1798); the poets (Wordsworth, etc.) who settled in that region (1814); boats on the North American Great Lakes (1887), and a person whose work is on lakes (1838); see lake (n.1). The U.S. professional basketball team began 1947 as the Minneapolis Lakers, where the name was appropriate; before the 1960-1 season it moved to Los Angeles, but kept the name.
Lakshmi: Hindu goddess of beauty, said to be from Sanskrit lakshmi "mark, fortune, riches, beauty."
lallygag (v.): "waste time, dilly-dally," 1862, American English; see lollygag. Related: Lallygagged; lallygagging.
lam (n.): "flight, escape," as in on the lam, 1928, in pickpocket slang, (according to OED attested from 1897 in do a lam), from a U.S. slang verb meaning "to run off" (1886), of uncertain origin, but perhaps from lam (v.), which was used in British student slang for "to beat" since 1590s (compare lambaste); if so, the word has the same etymological sense as the slang expression beat it.
lam (v.): also lamm, "to thrash, beat," 1590s, a slang, provincial or colloquial word, probably from Old Norse lemja "to beat," literally "to lame," which is cognate with the native verb lame (see lame (adj.)). Related: Lammed; lamming.
lama (n.): "Buddhist priest of Mongolia or Tibet," 1650s, according to OED from Tibetan blama "chief, high priest," with silent b-. Related: Lamaism; lamarchy. Lamasery "Buddhist monastery" (1849) is from French lamaserie, perhaps a word invented in French, as if from Persian sarai "an inn" (see caravanserai).
Lamarckian (adj.): "pertaining to the theories or work of French botanist and zoologist Jean-Baptiste Pierre Antoine de Monet de Lamarck" (1744-1829). Originally (1825) in reference to his biological classification system. He had the insight, before Darwin, that all plants and animals are descended from a common primitive life-form. But in his view the process of evolution included the inheritance of characteristics acquired by the organism by habit, effort, or environment. The word typically refers to this aspect of his theory, which was long maintained in some quarters but has since been rejected.
Lamaze (adj.): in reference to a method of childbirth technique, 1957, named for French obstetrician Dr. Fernand Lamaze (1891-1957), who promoted his methods of "psycho-prophylaxis," a form of childbirth preparation he had studied in the Soviet Union, in the West in the early 1950s.
lamb (n.): Old English lamb, lomb, Northumbrian lemb "lamb," from Proto-Germanic *lambaz (source also of Old Norse, Old Saxon, Old Frisian, Gothic lamb, Middle Dutch, Dutch lam, Middle High German lamp, German Lamm "lamb"). Common to the Germanic languages, but with no certain cognates outside them.

The Old English plural was sometimes lambru. A symbol of Christ (Lamb of God), typified by the paschal lamb, from late Old English. Applied to gentle or innocent persons (especially young Church members) from late Old English; from mid-15c. of persons easy to cheat ("fleece"). Also sometimes used ironically for cruel or rough characters (such as Kirke's Lambs in Monmouth's rebellion, 1684-86, "an ironical allusion to the device of the Paschal Lamb on their flag" [OED]); Farmer & Henley say "specifically applied to Nottingham roughs, and hence to bludgeon men at elections." Diminutive form lambie is attested from 1718. Lamb's-wool is from 1550s as a noun, 1825 (also lambswool) as an adjective.
lambada (n.): type of sensual Brazilian dance, 1988, from Portuguese, said in some sources to mean literally "a beating, a lashing." But others [Watkins] connect it ultimately to Latin lumbus "loin" (see lumbago).
lambaste (v.): 1630s, apparently from baste "to thrash" (see baste (v.3)) + the obscure verb lam "to beat, to lame" or the related Elizabethan noun lam "a heavy blow" (implied by 1540s in puns on lambskin). Compare earlier lamback "to beat, thrash" (1580s, used in old plays). A dictionary from c. 1600 defines Latin defustare as "to lamme or bumbast with strokes." Related: Lambasted; lambasting.
lambda (n.): Greek letter name, from a Semitic source akin to Hebrew lamedh.
lambdacism (n.): excessive use of the letter -l-, 1650s in writing, 1864 in pronunciation, from lambda + -ism.
lambency (n.): "quality of shining with a clear, soft light," 1817, from lambent (q.v.) + -cy. A figurative use, the etymological Latin sense "act or quality of licking" has been rare in English.
lambent (adj.): of light, flame, etc., "flowing or running over the surface," 1640s, from a figurative use of Latin lambentem (nominative lambens), present participle of lambere "to lick, lap, wash, bathe," from PIE root *lab-, indicative of smacking lips or licking (source also of Greek laptein "to sip, to lick," Old English lapian "to lick, lap up, to suck;" see lap (v.1)).
Lambert: masc. proper name, from French, from German Lambert, from Old High German Lambreht, from lant "land" (see land (N.)) + beraht "bright" (see bright (adj.)). Old English cognate was Landbeorht. The English popularity of the name 12c. and after probably is due to immigration from Flanders, where St. Lambert of Maestricht was highly venerated. Attested as a surname from mid-12c.
Lambeth: used metonymically for "Church of England, Archbishop of Canterbury," 1859, from the archbishop's palace in Lambeth, a South London borough. The place name is Old English lambehyðe, "place where lambs are embarked or landed." In church history, the Lambeth Articles were doctrinal statements written in 1595 by Archbishop of Canterbury John Whitgift. The Lambeth Walk was a Cockney song and dance, popularized in Britain 1937 in the revue "Me and my Gal," named for a street in the borough.
lambic (n.): also lambick, kind of strong Belgian beer, 1829, related to French alambic "a still" (see alembic).
lambkin (n.): 1570s, "little lamb" (mid-13c. as a surname), from lamb + diminutive suffix -kin.
lambskin (n.): "woolly skin of a lamb, used in dress or ornament," mid-14c., from lamb + skin (n.).
lame (adj.): Old English lama "crippled, lame; paralytic, weak," from Proto-Germanic *lamon "weak-limbed" (source also of Old Norse lami "lame, maimed," Dutch and Old Frisian lam, German lahm "lame"), literally "broken," from PIE root *lem- "to break; broken," with derivatives meaning "crippled" (source also of Old Church Slavonic lomiti "to break," Lithuanian luomas "lame").

In Middle English especially "crippled in the feet," but also "crippled in the hands; disabled by disease; maimed." Figurative sense of "imperfect" is from late 14c. Sense of "socially awkward" is attested from 1942. Noun meaning "crippled persons collectively" is in late Old English. To come by the lame post (17c.-18c.) was an old colloquialism in reference to tardy mails or news out-of-date.
lame (v.): "to make lame," c. 1300, from the root of lame (adj.). Compare Old Saxon lemon, Old Frisian lema, Dutch verlammen, German lähmen, Old Norse lemja "thrash, flog, beat; to lame, disable." Related: Lamed; laming.
lame (n.): also lamé, "silk interwoven with metallic threads," 1918, from a specialized sense of French lame, which generally meant "thin metal plate (especially in armor), gold wire; blade; wave (of the sea)," from Old French lame "thin strip, panel, blade, sheet, slice" (13c.), from Latin lamina, lamna "thin piece or flake of metal" (see laminate (v.)). The same French word was used in English earlier in armory as "a plate of metal" (1580s).
lame duck (n.): 1761, "any disabled person or thing;" especially Stock Exchange slang for "defaulter."
A lame duck is a man who cannot pay his differences, and is said to waddle off. [Thomas Love Peacock, "Gryll Grange," 1861]
Sometimes also in naval use for "an old, slow ship." Modern sense of "public official serving out term after an election" is recorded by 1863, American English. The quote attributed to President Lincoln ("[A] senator or representative out of business is a sort of lame duck. He has to be provided for") is from an anecdote of 1878.
It is well known to everybody who knows anything of its history, that this court [Court of Claims] was made a sort of retreat for lame duck politicians that got wounded and had to retreat before the face of popular condemnation. That is just exactly what it was for, a safe retreat for lame ducks; and it was so filled up; (etc.) [Sen. John P. Hale, New Hampshire, "Congressional Globe," Jan. 12, 1863, p.271]
lame-brain (n.): "stupid person," 1921, from lame (adj.) + brain (n.).
lamely (adv.): 1590s, from lame (adj.) + -ly (2).
lameness (n.): 1520s, from lame (adj.) + -ness.
lament (v.): mid-15c., back-formation from lamentation or else from Old French lamenter "to moan, bewail" (14c.) and directly from Latin lamentari "to wail, moan, weep, lament," from lamentum "a wailing, moaning, weeping." Related: Lamented; lamenting.
lament (n.): 1590s, "expression of sorrow or grief," from Middle French lament and directly from Latin lamentum "a wailing, moaning, weeping" (see lamentation). From 1690s as "a mourning song."
lamentable (adj.): c. 1400, from Middle French lamentable and directly from Latin lamentabilis "full of sorrow, mournful; lamentable, deplorable," from lamentari "to wail, moan, weep" (see lamentation). Related: Lamentably.