Online Etymology Dictionary

Laos: Southeast Asian land, from the name of legendary founder Lao. Related: Laotian.
lap (n.): Old English læppa (plural læppan) "skirt or flap of a garment," from Proto-Germanic *lapp- (cf. Old Frisian lappa, Old Saxon lappo, Middle Dutch lappe, Dutch lap, Old High German lappa, German Lappen "rag, shred," Old Norse leppr "patch, rag"), from PIE root *leb- "be loose, hang down."

Sense of "lower part of a shirt" led to that of "upper legs of seated person" (c.1300). Used figuratively ("bosom, breast") from late 14c.; e.g. lap of luxury, first recorded 1802. From 15c.-In 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]
That this is pleasure and not torment for the client is something survivors of the late 20c. will have to explain to their youngers.
lap (v.1): "take up liquid with the tongue," from Old English lapian "to lap up, drink," from Proto-Germanic *lapajanan (cf. Old High German laffen "to lick," Old Saxon lepil, Dutch lepel, German Löffel "spoon"), from PIE imitative base *lab- (cf. Greek laptein "to sip, lick," Latin lambere "to lick"), indicative of licking, lapping, smacking lips. Meaning "splash gently" first recorded 1823, based on similarity of sound. Related: Lapped; lapping.
lap (v.2): "to lay one part over another," early 14c., "to surround (something with something else)," from lap (n.). Figurative use, "to envelop (in love, sin, desire, etc.)" is from mid-14c. The sense of "to get a lap ahead (of someone) on a track" is from 1847, on notion of "overlapping." The noun in this sense is 1670s, originally "something coiled or wrapped up;" meaning "a turn around a track" (1861) also is from this sense. Related: Lapped; lapping; laps.
laparoscopy (n.): 1855, from -scopy + Greek lapara "flank," from laparos "soft," from PIE *lep- "to peel." Related: Laparoscopic; laparoscope.
lapdog (n.): also lap-dog, 1640s, from lap (n.) + 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.): 1751 (implied in lapelled), from lap (n.) + -el, diminutive suffix. Cf. lappet.
lapful (n.): 1610s, from lap (n.) + -ful.
lapidary (n.): "one skilled in working with precious stones," late 14c., from Old French lapidaire (12c.), from Latin lapidarius "stonecutter," originally an adjective "of or working with stone," from lapis (genitive lapidis) "stone." Meaning "a treatise on precious stones" is late 14c. Related: Lapidarist.
lapidation (n.): "stoning to death," 1610s, from Latin lapidationem (nominative lapidatio), noun of action from past participle stem of lapidare "to throw stones at," from the stem of lapis "stone."
lapis lazuli (n.): early 15c., from Middle Latin lapis lazuli, literally "stone of azure," from Latin lapis "stone" + Medieval Latin lazuli, genitive of lazulum, from Arabic lazuward (see azure).
Laplace: in scientific phrases, a reference to French astronomer and mathematician Pierre Simon, Marquis de Laplace (1749-1827).
Lapland: 1570s, from Lapp, the Swedish name for this Finnic people (their name for themselves was Sabme), which probably originally was an insulting coinage (cf. Middle High German lappe "simpleton"). In English traditionally the home of witches and wizards who had power to conjure winds and tempests. Related: Laplander.
Lapp: 1859; see Lapland.
lappet (n.): "a small flap," 1570s; earlier "lobe of a body part" (early 15c.), from Middle English lappe "lap" (see lap (n.)) + -et, diminutive suffix.
lapse (n.): mid-15c., "elapsing of time, expiration;" also "temporary forfeiture of a legal right," from Middle French laps "lapse," from Latin lapsus "a slipping and falling, flight (of time), falling into error," from labi "to slip, glide, fall." Meaning "moral transgression, sin" is c.1500; that of "slip of the memory" is 1520s; that of "a falling away from one's faith" is from 1650s.
lapse (v.): early 15c., said to be from lapse (n.) or from Latin lapsare "to lose one's footing." Related: Lapsed; lapses; lapsing.
laptop: also lap-top, as a type of portable computer, 1984, from lap (n.) + top (1), on model of desktop.
lapwing (n.): Middle English lappewinke (late 14c.), lapwyngis (early 15c.), folk etymology alteration of Old English hleapewince, probably literally "leaper-winker," from hleapan "to leap" + wince "totter, waver, move rapidly," related to wincian "to wink." 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, from 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" + bord "ship's side." Altered 16c. on influence of starboard, then largely replaced by the specialized sense of port (n.1). to avoid confusion of similar-sounding words. The Old English term was bæcboard, literally "back board" (see starboard).
larcenist (n.): 1803, from larceny + -ist. Earlier was larcener (1630s).
larcenous (adj.): 1742, from larceny + -ous.
larceny (n.): late 15c., with -y (3) + Anglo-French larcin (late 13c.), from Old French larrecin, larcin "theft, robbery" (11c.), from Latin latrocinium "robbery, freebooting, highway-robbery, piracy," from latro "robber, bandit," also "hireling, mercenary," ultimately from a Greek source akin to latron "pay, hire, wages," from a suffixed form of PIE root *le- "to get."
larch (n.): 1540s, from German Lärche, from Middle High German larche, from Old High German *larihha, from Latin larix (genitive laricis), probably a loan-word from an Alpine Gaulish language, corresponding phonetically to Old Celtic *darik- "oak" (see Druid and tree).
lard (n.): late 14c. (possibly early 13c.), "rendered fat of a swine," from Old French larde "joint, meat," especially "bacon fat" (12c.), and directly from Latin lardum "lard, bacon, cured swine's flesh," probably cognate with Greek larinos "fat," laros "pleasing to the taste."
lard (v.): "prepare (meat) for roasting by inserting of pieces of salt pork, etc., into it," mid-14c., from Old French larder "to lard" (12c.), from lard "bacon fat" (see lard (n.)). Figuratively, of speech or writing, from 1540s. Related: Larded; larding.
larder (n.): c.1300, "supply of salt pork, bacon, and other meats," later in reference to the room for processing and storing such (late 14c.), from Anglo-French larder, Old French lardier "a place for meats," from Medieval Latin lardarium "a room for meats," from Latin lardum "lard, bacon" (see lard (n.)). Meaning "department of the royal household or of a monastic house in charge of stored meats" is mid-15c. Surname Lardner "person in charge of a larder" is attested from mid-12c.
lardy (adj.): 1879, from lard (n.) + -y (2). Related: Lardiness.
lares (n.): "Roman tutelary gods, household deities," Latin, plural of lar.
large (adj.): c.1200, "bountiful, inclined to give or spend freely," also, of areas, "great in expanse," from Old French large "broad, wide; generous, bounteous," from Latin largus "abundant, copious, plentiful; bountiful, liberal in giving," of unknown origin. Main modern meanings "extensive; big in overall size" emerged 14c. An older sense of "liberated, free from restraining influence" is preserved in at large (late 14c.). Adjective phrase larger-than-life first attested 1937 (bigger than life is from 1640s).
largely (adv.): c.1200, "liberally, generously, bountifully;" also "in large measure; abundantly," from large + -ly (2). Meaning "extensively, to a great extent" is c.1400.
largeness (n.): c.1300, from large + -ness.
larger: comparative of large (q.v.).
largesse (n.): also largess, "willingness to give or spend freely; munificence," c.1200, from Old French largesse "a bounty, munificence," from Vulgar Latin *largitia "abundance," from Latin largus "abundant" (see large). In medieval theology, "the virtue whose opposite is avarice, and whose excess is prodigality" ["Middle English Dictionary"].
largest (adj.): superlative of large (q.v.).
lariat (n.): 1832, American English, from Spanish la reata "the rope," from reatar "to tie against," from re- "back" + atar "to tie," from Latin aptare "to join" (see adapt).
lark (n.1): "songbird," early 14c., earlier lauerche (c.1200), from Old English lawerce (late Old English laferce), from Proto-Germanic *laiw(a)rikon (cf. Old Saxon lewerka, Frisian liurk, Old Norse lævirik, Dutch leeuwerik, German Lerche), of unknown origin. Some Old English and Old Norse forms suggest a compound meaning "treason-worker," but there is no folk tale to explain or support this.
lark (n.2): "spree, frolic," 1811, possibly shortening of skylark (1809), sailors' slang "play rough in the rigging of a ship" (larks were proverbial for high-flying), or from English dialectal lake/laik "to play" (c.1300, from Old Norse leika "to play," from PIE *leig- "to leap") with intrusive -r- common in southern British dialect. The verb lake, considered characteristic of Northern English vocabulary, is the opposite of work but lacks the other meanings of play. As a verb, from 1813. Related: Larked; larking.
larking (n.): "fun, frolicking," 1813, from present participle of lark (v.); see lark (n.2).
larkspur (n.): type of plant, 1570s, from lark (n.) + spur (n.); so called from resemblance to the bird's large hind claws.
larrup (v.): "to beat, thrash," 1823, of unknown origin, possibly related to Dutch larpen "to thrash." First mentioned as a Suffolk dialect word.
Larry: masc. proper name, often a familiar form of Lawrence.
larva (n.): 1650s, "a ghost, specter," from Latin larva (plural larvae), earlier larua "ghost," also "mask;" applied in biological sense 1768 by Linnaeus because immature forms of insects "mask" the adult forms. On the double sense of the Latin word, Carlo Ginzburg, among other students of mythology and folklore, has commented on "the well-nigh universal association between masks and the spirits of the dead."
larvae (n.): plural of larva (q.v.).
larval (adj.): 1650s, from Latin larvalis, from larva (see larva).
laryngeal (adj.): 1795, from medical Latin laryngeus, from Greek larynx (see larynx) + English -al (1).
laryngitis (n.): 1822, Medical Latin, from comb. form of larynx (q.v.) + -itis.
larynx (n.): 1570s, from Middle French larynx (16c.), from Modern Latin, from Greek larynx (genitive laryngos) "the upper windpipe," probably from laimos "throat," influenced by pharynx "throat, windpipe."
lasagna (n.): "pasta cut in long, wide strips; a dish made from this," 1760 (as an Italian word in English), from Italian (plural is lasagne), from Vulgar Latin *lasania, from Latin lasanum "a pot," from Greek lasanon "pot with feet, trivet."
lascar (n.): East Indian sailor, 1620s, from Portuguese lachar, from Hindi lashkari "soldier, native sailor," from lashkar "army, camp," from Persian lashkar. Cf. Arabic al-'askar "the army," perhaps from Persian.