Online Etymology Dictionary

lane (n.): Old English lane, lanu "narrow hedged-in road," common Germanic (cognates: Old Frisian lana, Middle Dutch lane, Dutch laan "lane, alley, avenue," Old Norse lön "small, oblong hayrick," in modern use "row of houses"), but of unknown origin. From early 15c. as "any well-defined track;" as "one track of a marked road" from 1921, American English.
lang syne: "long ago," c. 1500, Scottish dialect variant of long since; popularized in Burns' song, 1788. Century Dictionary has langsyner "person who lived long ago."
Langobard: see Lombard. Related: Langobardic.
language (n.): late 13c., langage "words, what is said, conversation, talk," from Old French langage "speech, words, oratory; a tribe, people, nation" (12c.), from Vulgar Latin *linguaticum, from Latin lingua "tongue," also "speech, language," from PIE *dnghu- "tongue" (see tongue (n.)).

The -u- is an Anglo-French insertion (see gu-); it was not originally pronounced. Meaning "manner of expression" (vulgar language, etc.) is from c. 1300. Meaning "a language," as English, French, Arabic, etc., is from c. 1300; Century Dictionary" defines this as: "The whole body of uttered signs employed and understood by a given community as expressions of its thoughts; the aggregate of words, and of methods of their combination into sentences, used in a community for communication and record and for carrying on the processes of thought." In Middle English the word also was used of dialects:
Mercii, þat beeþ men of myddel Engelond[,] vnderstondeþ bettre þe side langages, norþerne and souþerne, þan norþerne and souþerne vnderstondeþ eiþer oþer. [John of Trevisa, translation of Bartholomew de Glanville's "De proprietatibus rerum," 1398]

In oþir inglis was it drawin, And turnid ic haue it til ur awin Language of the norþin lede, Þat can na noþir inglis rede. ["Cursor Mundi," early 14c.]
Language barrier attested from 1885.
Languedoc (n.): language of the south of France in the Middle Ages, the language of the troubadours (Provençal is one of its principal branches), 1660s, from French langue d'oc "speech of the south of France," literally "the language of 'yes,' " from oc, the word used south of the Loire for "yes," which is from Latin hoc "this," which in Vulgar Latin came to mean "yes" (see oui). The name also was given to one of the provinces where it was spoken. Opposed to langue d'oïl, from the way of saying "yes" in the north of France, from Old French oïl (Modern French oui). The langue d'oïl developed into standard Modern French. Related: Languedocian.

Langue d'oc was truer to Latin than Old French or Castilian Spanish were, and had fewer Germanic words. Dante considered it a separate language, and it and the northern French were not always mutually intelligible. Jonathan Sumption's "The Albigensian Crusade" [Faber and Faber, 1978] refers to a court official at Albi "who in 1228 referred to a seal as bearing an inscription in 'French or some other foreign language.'" The French authorities began to repress langue d'oc in 16c.
languet (n.): "something in the shape of a little tongue," early 15c., from Old French languete (Modern French languette), literally "little tongue," diminutive of langue "tongue," from Latin lingua "tongue" (see lingual). As the name of a kind of hood in 17c. women's dress it probably is a separate borrowing of the French word.
languid (adj.): 1590s, from Middle French languide (16c.) and directly from Latin languidus "faint, listless, and sluggish from weakness, fatigue, or want of energy," from languere "be weak, be fatigued, be faint, be listless," from PIE *langu-, from root *(s)leg- "to be slack" (see lax). Related: Languidly; languidness.
languish (v.): early 14c., "fail in strength, exhibit signs of approaching death," from languiss-, present participle stem of Old French languir "be listless, pine, grieve, fall ill" (12c.), from Vulgar Latin *languire, from Latin languere "be weak or faint" (see lax). Weaker sense of "be lovesick, grieve, lament, grow faint," is from mid-14c. Related: Languished; languishing.
languishing (adj.): mid-14c., present participle adjective from languish (v.). Related: Languishingly.
languishment (n.): 1540s, "sorrow caused by love;" 1590s, "sickness; m,ental distress," from languish (v.) + -ment.
languor (n.): c. 1300, "disease, sickness; distress, mental suffering," from Old French langor "sickness; weakness" (12c., Modern French langueur), from Latin languorem (nominative languor) "faintness, feebleness, lassitude," from languere "be weak or faint" (see lax). Sense in English shifted to "faintness, weariness" (1650s) and "habitual want of energy" (1825).
languorous (adj.): late 15c., "mournful," from Old French langoros "ill, ailing, suffering, languishing" (11c., Modern French langoureux), from langor "sickness, weakness" (see languor). Meaning "suggestive of languor, weariness, or want of energy," often with a suggestion of seductiveness, is from 1821. Related: Languorously; languorousness.
Lanier: surname, from Old French lainier "wool-monger," from Latin lana "wool" (see wool).
lank (adj.): Old English hlanc "loose and empty, meagerly slim, flaccid," from Proto-Germanic *hlanka-, forming words meaning "to bend, turn," perhaps from PIE root *kleng- "to bend, turn," with a connecting notion of "flexible" (compare German lenken "to bend, turn aside;" see flank (n.)). In Middle English, "Some examples may be long adj. with unvoicing of g" ["Middle English Dictionary"]. In reference to hair, "straight and flat," from 1680s. Related: Lankness (1640s).
lanky (adj.): 1630s, "straight and flat," used of hair, from lank (adj.) + -y (2). Sense of "awkwardly tall and thin" is first recorded 1818. Fowler writes that "The short form is almost only literary, the long chiefly colloquial." Related: Lankily (1848); lankiness (1846).
lanolin (n.): fatty matter extracted from sheep's wool, 1885, from German Lanolin, coined by German physician Mathias Eugenius Oscar Liebreich (1838-1908) from Latin lana "wool" (from PIE root *wele- (1) "wool;" see wool) + oleum "oil, fat" (see oil (n.)) + chemical suffix -in (2).
lant (n.): "stale urine used for industrial purposes, chamber-lye," Old English hland.
lantern (n.): mid-13c., from Old French lanterne "lamp, lantern, light" (12c.), from Latin lanterna "lantern, lamp, torch," altered (by influence of Latin lucerna "lamp") from Greek lampter "torch, beacon fire," from lampein "to shine, give light, be brilliant" (from PIE root *lap- "to light, burn;" see lamp).

Variant lanthorn (16c.-19c.) was folk etymology based on the common use of horn as a translucent cover. Lantern-jaws "hollow, long cheeks" is from a resemblance noted since at least mid-14c.; Johnson suggests the idea is "a thin visage, such as if a candle were burning in the mouth might transmit the light."
lanthanum (n.): metallic rare earth element, 1841, coined in Modern Latin by Swedish chemist and mineralogist Carl Gustav Mosander (1797-1858), who discovered it in 1839, from Greek lanthanein "to lie hidden, escape notice," from PIE root *ladh- "to be hidden" (see latent). So called because the element was "concealed" in the earth from which he extracted it.
lanyard (n.): also laniard, "small rope or cord used aboard ships," alternative spelling (influenced by nautical yard (2) "long beam used to support a sail") of Middle English lainer, "thong for fastening parts of armor or clothing" (late 14c.), from Old French laniere "thong, lash, strap of leather," from lasniere (12c., from lasne "strap, thong"), apparently altered (by metathesis and influence of Old French las "lace") from nasliere (nasle), from Frankish *nastila or some other Germanic source, from Proto-Germanic *nastila- (source also of Old High German, Old Saxon nestila "lace, strap, band," German nestel "string, lace, strap"), from PIE root *ned- "to knot."
Lao: Tai people of Southeast Asia, 1882; see Laos. In reference to their dialects, by 1939.
Laocoon: also Laocoön name of a Trojan priest of Apollo, from Latin Laocoon, from Greek Laukoun, from laos "people" (see lay (adj.)) + koeo "I mark, perceive."
Laocoön, n. A famous piece of antique sculpture representing a priest of that time and his two sons in the folds of two enormous serpents. The skill and diligence with which the old man and lads support the serpents and keep them up in their work have been justly regarded as one of the noblest artistic illustrations of the mastery of human intelligence over brute inertia. [Ambrose Bierce, "Devil's Dictionary," 1911]
Laodicean (adj.): "lukewarm in religion," 1560s, from Laodicea, ancient city of Phrygia Minor (modern Latakia in Syria) whose early Christians were chastised in the Bible for indifference to their religion [Rev. iii:14-16]. The city is said to be named for the 3c B.C.E. Syrian queen Laodice, wife of Antiochus II.
Laos: Southeast Asian land, from the name of legendary founder Lao. Related: Laotian (1861).
lap (v.1): "lick up (liquid), take into the mouth with the tongue," from Old English lapian "to lap up, drink," from Proto-Germanic *lapojan (source also of Old High German laffen "to lick," Old Saxon lepil, Dutch lepel, German Löffel "spoon"), from PIE imitative base *lab- (source also of Greek laptein "to sip, lick," Latin lambere "to lick"), indicative of licking, lapping, smacking lips.

Of water, "splash gently, flow against" first recorded 1823, based on similarity of sound. Figurative use of lap (something) up "receive it eagerly" is by 1890. Related: Lapped; lapping. The noun meaning "liquid food; weak beverage" is from 1560s.
lap (v.2): early 14c., "to surround (something with something else)," from lap (n.1). Figurative use, "to envelop (in love, sin, desire, etc.)" is from mid-14c. Meaning "lay one part over another, lay in such a way as to cover part of something underneath" is from c. 1600. The sense of "to get a lap ahead (of a competitor) on a track" is from 1847, on notion of "overlapping" (see lap (n.2)). Related: Lapped; lapping.
lap (n.2): 1670s, "something coiled or wrapped up," from lap (v.2). Meaning "part of one thing that lies on and covers another" is from 1800. Meaning "a turn around a track" in a distance race is from 1861. Related: laps.
lap (n.1): Old English læppa (plural læppan) "skirt or flap of a garment," from Proto-Germanic *lapp- (source also of Old Frisian lappa, Old Saxon lappo, Middle Dutch lappe, Dutch lap, Old High German lappa, German Lappen "rag, shred," Old Norse leppr "patch, rag"), of uncertain origin.

Sense of "lower front part of a shirt or skirt" led to that of "upper legs of seated person" (c. 1300). Used figuratively ("bosom, breast, place where someone or something is held and cherished") from late 14c., as in lap of luxury (which is first recorded 1802). To drop or dump something in someone's lap "shift a burden" is from 1962. From 15c.-17c. the word (often in plural) was a euphemism for "female pudendum," but this is not the source of lap dance, which is first recorded 1993.
To lap dance, you undress, sit your client down, order him to stay still and fully clothed, then hover over him, making a motion that you have perfected by watching Mister Softee ice cream dispensers. [Anthony Lane, review of "Showgirls," "New Yorker," Oct. 16, 1995]
Lap-clap was old slang for "an act of coition" (c. 1600), in warning expressions to youth often paired with lip-clip "a kiss." Also compare slang Lapland "the society of women."
laparoscopy (n.): 1855, from -scopy + comb. form of Greek lapara "flank, loins, soft part of the body between the ribs and the hips," from laparos "soft, slack, loose," from PIE *lap-aro-, suffixed form of root *lep- (1) "to peel" (see leper). Related: Laparoscopic; laparoscope.
lapdog (n.): also lap-dog, 1640s, "small dog fondled in the lap," from lap (n.1) + dog (n.); figurative sense of "subservient person" is by 1950.
Senator McCarthy (R-Wis) renewed his Communists-in-Government charges today and called Senator Tydings (D-Md) the Truman administration's "whimpering lap dog." [AP news story, Aug. 7, 1950]
lapel (n.): part of a garment folded back and overlapping another, 1751 (implied in lapelled), from lap (n.2) + -el (2), diminutive suffix. Compare lappet.
lapful (n.): 1610s, from lap (n.1) + -ful. In old slang, "a lover or husband," also "an unborn child."
lapidary (n.): "one skilled in working with precious stones," late 14c., from Old French lapidaire "stonecutter," also "treatise on precious stones" (12c.), from Latin lapidarius "stonecutter," originally an adjective "of or working with stone," from lapis (genitive lapidis) "stone" (see lapideous). Meaning "a treatise on precious stones" is late 14c. As an adjective in English from 1724. Related: Lapidarist.
lapidation (n.): "stoning to death," 1610s, from Latin lapidationem (nominative lapidatio) "a throwing of stones, stoning," noun of action from past participle stem of lapidare "to throw stones at," from the stem of lapis "stone" (see lapideous). Related: Lapidate (v.), 1620s.
lapideous (adj.): "stony," 1640s, from Latin lapideus, from lapid-, stem of lapis "a stone, pebble," from Proto-Italic *laped-, which de Vaan writes is "Probably a Mediterranean loanword," with cognates in Greek: lepas "bare rock, mountain," lepas "limpet," lepades "molluscs which stick to rocks."
lapidification (n.): "action or process of turning to stone," 1620s, from stem of Latin lapis "stone" (see lapideous) + -ficationem (nominative -ficatio), forming nouns of action from verbs in -ficare (compare -fy). Related: Lapidify; lapidified.
lapidocolous (adj.): of beetles, "living under stones," 1888, from Latin lapis "a stone" (see lapideous) + colus "inhabiting," from colere "to inhabit" (see colony).
lapis lazuli (n.): "azure-stone, rich ultramarine silicate stone," early 15c., from Middle Latin lapis lazuli, literally "stone of azure," from Latin lapis "a stone" (see lapideous) + Medieval Latin lazuli, genitive of lazulum, from Arabic lazuward (see azure).
Lapith: ancient people of Thessaly, c. 1600, Greek Lapithoi; they were celebrated for their battle with the centaurs, a favorite theme of Greek art.
Laplace: in scientific phrases, a reference to French astronomer and mathematician Pierre Simon, Marquis de Laplace (1749-1827). Related: Laplacian (1836).
Lapland: northernmost part of the Scandinavian peninsula, 1570s, from Lapp, the Swedish name for this Finnic people (their name for themselves was Sabme), which probably originally was an insulting coinage (compare Middle High German lappe "simpleton"). "Formerly, the fabled home of witches and magicians, who had power to send winds and tempests" [OED]. Related: Laplander.
Lapp: 1859; see Lapland. Related: Lappish.
lappet (n.): "a small flap," 1570s; earlier "lobe of a body part" (early 15c.), from Middle English lappe "lap" (see lap (n.1)) + -et, diminutive suffix.
lapse (v.): early 15c., to go by, pass (of time), from lapse (n.) and from Latin lapsare "to lose one's footing, slip, slide," from stem of labi "to slip, glide, fall." Meaning "fail in duty or faith" is from 1630s. Meaning "become void, revert due to some failure or non-action by the holder" is from 1726. Related: Lapsed; lapses; lapsing.
lapse (n.): mid-15c., "elapsing of time, expiration;" also "temporary forfeiture of a legal right" due to some failure or non-action by the holder, from Middle French laps "lapse," from Latin lapsus "a slipping and falling, a landslide; flight (of time); falling into error," from labi "to glide, slip, slide, sink, fall; decline, go to ruin," which is of unknown etymology.

Meaning "moral transgression, sin" is from c. 1500; that of "slip of the memory" is 1520s; that of "a falling away from one's faith" is from 1650s.
lapsed (adj.): of persons, "fallen away from the faith," 1630s, past participle adjective from lapse (v.). Originally especially to those who denied Christianity during prosecution.
laptop: also lap-top, in reference to a type of portable computer, 1983 (adjective and noun), from lap (n.1) + top (n.1), on model of desktop.
lapwing (n.): Middle English lappewinke (late 14c.), lapwyngis (early 15c.), folk etymology alteration of Old English hleapewince "lapwing," probably literally "leaper-winker," from hleapan "to leap" (see leap (v.)) + wince "totter, waver, move rapidly," related to wincian "to wink" (see wink (v.)).

Said to be so called from "the manner of its flight" [OED] "in reference to its irregular flapping manner of flight" [Barnhart], but the lapwing also flaps on the ground pretending to have a broken wing to lure egg-hunters away from its nest, which seems a more logical explanation. Its Greek name was polyplagktos "luring on deceitfully."
larboard (n.): "left-hand side of a ship" (to a person on board and facing the bow), 1580s, alteration of Middle English ladde-borde (c. 1300), perhaps literally "the loading side," if this was the side on which goods were loaded onto a ship, from laden "to load" (see lade) + bord "ship's side" (see board (n.2)).

Altered 16c. by influence of starboard, then, to avoid confusion of similar-sounding words, it was largely replaced by the specialized sense of port (n.1). The Old English term for it was bæcbord, literally "back board" (see starboard), a term which remains in the other Germanic tongues.
larcenist (n.): "thief," 1803, from larceny + -ist. Earlier was larcener (1630s).