Online Etymology Dictionary

low-class (adj.): 1868, from low (adj.) + class (n.).
low-down (adj.): also low down, lowdown, "vulgar," 1888, from low (adj.) + down (adv.). Earlier it meant "humble" (1540s). As a noun, 1915, from the adjective, American English.
low-grade (adj.): 1867, originally in mining, with reference to ores, from low (adj.) + grade (n.).
low-life (adj.): "disreputable, vulgar," 1794, from low (adj.) + life; as a noun, "coarse, no-good person" it is recorded from 1911. Also lowlife.
low-profile (adj.): 1957, in reference to automobile wheels, from low (adj.) + profile (n.). General sense by 1970, American English, in reference to Nixon Administration policy of partial U.S. disengagement from burdensome commitments abroad.
lowboy (n.): "chest of drawers on short legs," 1891, a hybrid from low (adj.) + French bois "wood" (see bush).
lowbrow (n.): also low-brow, "person who is not intellectual," 1902, from low (adj.) + brow. Said to have been coined by U.S. journalist Will Irwin (1873-1948), perhaps on the model of highbrow, which seems to be earlier. A low brow on a man as a sign of primitive qualities was common in 19c. fiction, but it also was considered a mark of classical beauty in women.
A low brow and not a very high one is considered beautiful in woman, whereas a high brow and not a low one is the stamp of manhood. ["Medical Review," June 2, 1894]
As an adjective from 1913.
lower (v.1): c. 1600, "to descend, sink," from lower (adj.), from Middle English lahghere (c. 1200), comparative of low (adj.). Transitive meaning "to let down, to cause to descend" attested from 1650s. Related: Lowered; lowering. In the sense "to cause to descend" the simple verb low (Middle English lahghenn, c. 1200) was in use into the 18c.
lower (v.2): "to look dark and threatening," also lour, Middle English louren, luren "to frown" (early 13c.), "to lurk" (mid-15c.), from Old English *luran or from its cognates, Middle Low German luren, Middle Dutch loeren "lie in wait." Form perhaps assimilated to lower (1). Related: Lowered; lowering.
lower (adj.): c. 1200, lahre, comparative of lah (see low (adj.)).
lower-case (adj.): also lowercase, 1680s; see lower (adj.) + case (n.2).
lowercase (v.): "to set (text) in lower-case type," 1911, from lower-case (adj.). Related: Lowercased; lowercasing.
lowermost: 1560s, from lower (adj.) + -most.
lowest (adj.): c. 1200, laghesst, superlative of lah (see low (adj.)).
Lowestoft (n.): type of porcelain, named for a town in Suffolk where it was made from 1757.
lowing (n.): early 13c., verbal noun from low (v.).
lowland (n.): c. 1500, originally with reference to Scotland, from low (adj.) + land (n.). Related: Lowlander.
lowliness (n.): early 15c., from lowly + -ness.
lowly: c. 1300 (adv.); late 14c. (adj.) "humble," from low (adj.) + -ly.
lowness (n.): early 13c., from low (adj.) + -ness.
lox (n.): 1934, American English, from Yiddish laks, from Middle High German lahs "salmon," from Proto-Germanic *lakhs-, from the common IE root for the fish, *laks- (source also of Lithuanian laszisza, Russian losos, Polish łosoś "salmon").
loxo-: word-forming element meaning "oblique," before vowels lox-, from Greek loxos "slanting, crosswise, oblique." E.g. loxodromics "art of oblique sailing."
loyal (adj.): 1530s, in reference to subjects of sovereigns or governments, from Middle French loyal, from Old French loial, leal "of good quality; faithful; honorable; law-abiding; legitimate, born in wedlock," from Latin legalem, from lex "law." In most cases it has displaced Middle English leal, which is from the same French source. Sense development in English is feudal, via notion of "faithful in carrying out legal obligations." In a general sense (of dogs, lovers, etc.), from c. 1600. As a noun meaning "those who are loyal" from 1530s (originally often in plural).
loyalism (n.): 1812, from loyal + -ism.
loyalist (n.): 1680s, from loyal + -ist. Meaning different persons in different times and places.
loyally (adv.): 1570s, from loyal + -ly (2).
loyalty (n.): c. 1400, from Old French loialté, leauté "loyalty, fidelity; legitimacy; honesty; good quality" (Modern French loyauté), from loial (see loyal). Earlier leaute (mid-13c.), from the older French form. Loyalty oath first attested 1852.
lozenge (n.): figure having four equal sides and two acute and two obtuse angles, early 14c., from Old French losenge "windowpane, small square cake," etc., used for many flat quadrilateral things (Modern French losange). It has cognates in Spanish losanje, Catalan llosange, Italian lozanga. Probably from a pre-Roman Celtic language, perhaps Iberian *lausa or Gaulish *lausa "flat stone" (compare Provençal lausa, Spanish losa, Catalan llosa, Portuguese lousa "slab, tombstone"), from a pre-Celtic language.

Originally in English a term in heraldry; meaning "small cake or tablet (originally diamond-shaped) of medicine and sugar, etc., meant to be held in the mouth and dissolved" is from 1520s.
LP: 1948, abbreviation of long-playing phonograph record.
The most revolutionary development to hit the recording industry since the invention of the automatic changer is the Long Playing record, which can hold an entire 45-minute symphony or musical-comedy score on a single 12-inch disk. ... The disks, released a few weeks ago by Columbia Records and made of Vinylite, have phenomenally narrow grooves (.003 of an inch). They are played at less than half the speed of the standard old-style records. ["Life" magazine, July 26, 1948]
LSD: "lysergic acid diethylamide," 1950, from German "Lysergsäure-diäthylamid" (abbreviated LSD in a Swiss journal from 1947). See lysergic. L.s.d. as the abbreviation of "pounds, shillings, and pence" is recorded from 1853.
Ltd.: abbreviation of limited, attested by 1900.
luau (n.): Hawaiian party or feast, 1853, from Hawaiian lu'au, literally "young taro tops," which were served at outdoor feasts.
lubber (n.): mid-14c., "big, clumsy, stupid fellow who lives in idleness," from lobre, earlier lobi "lazy lout," probably of Scandinavian origin (compare Swedish dialectal lubber "a plump, lazy fellow"). But OED suggests a possible connection with Old French lobeor "swindler, parasite," with sense altered by association with lob (n.) in the "bumpkin" sense. A sailors' word since 16c. (as in landlubber), but earliest attested use is of lazy monks (abbey-lubber). Compare also lubberwort, the name of the mythical herb that produces laziness (1540s); and Lubberland "imaginary land of plenty without work" (1590s). Sometimes also Lubbard (1580s).
lubber (v.): 1520s, from lubber (n.). Related: Lubbered; lubbering.
lubberly (adj.): 1570s, from lubber (n.) + -ly (1).
lube: 1934, colloquial shortening of lubrication. As a verb (short for lubricate) recorded from 1961.
Lubish: 1610s, from German lübisch, Dutch lubeksch, from Lübeck, Hanseatic city in northern Germany, formerly a trade center, hence its use as an adjective in English. The city was founded 1143 and is said to be named for the former principality of the Liubichi, literally "the people of prince Liub" (literally "beloved").
lubric (adj.): "smooth, slippery," late 15c., also "lascivious, wanton," from Middle French lubrique (15c.) or directly from Latin lubricus "slippery" (see lubricant (adj.)). Related: Lubrical.
lubricant (n.): 1828, probably from lubricant (adj.), or from Latin lubricantem.
lubricant (adj.): "reducing friction," 1809, from Latin lubricantem (nominative lubricans), present participle of lubricare "to make slippery or smooth," from lubricus "slippery; easily moved, sliding, gliding;" figuratively "uncertain, hazardous, dangerous; seductive," from PIE *sleubh- "to slip, slide" (see sleeve).
lubricate (v.): 1620s, "to make slippery or smooth" (especially by the application of an oil), from Latin lubricatus, past participle of lubricare "to make slippery or smooth," from lubricus "slippery" (see lubricant (adj.)). Related: Lubricated; lubricating. Earlier verb was lubrify (1610s), from Medieval Latin lubrificare.
lubrication (n.): 1640s, "act of lubricating," noun of action from lubricate (v.). Earlier were lubifraction (1540s).
lubricity (n.): late 15c., "lasciviousness," from Middle French lubricité or directly from Latin lubricitatem (nominative lubricitas), from lubricus "slippery" (see lubricant (adj.)). Sense of "oiliness, smoothness" is from 1540s; figurative sense of "shiftiness" is from 1610s.
The priests had excellent cause to forbid us lechery: this injunction, by reserving to them acquaintance with and absolution for these private sins, gave them an incredible ascendancy over women, and opened up to them a career of lubricity whose scope knew no limits. [Marquis de Sade, "Philosophy in the Bedroom"]
lubricous (adj.): 1530s, "lascivious," from Latin lubricus "slippery, smooth," from lubricus "slippery" (see lubricant (adj.)). Literal meaning "slippery, oily" is from 1650s in English; figurative sense of "shifty, elusive" is from 1640s. Also lubricious (1580s).
lubritorium (n.): "place where automobiles are greased," 1928; from lubrication + ending from auditorium. Mentioned as an overworked suffix in the late 1920s; Mencken also lists infantorium, shavatorium, restatorium, hatatorium, and odditorium ("a slide-show").
lucency (n.): 1650s, from lucent + -cy. Lucence is from late 15c.
lucent (adj.): mid-15c., "shining, bright, luminous," from Latin lucentem (nominative lucens), present participle of lucere "to shine" (see light (n.)). Meaning "lucid, clear" is from 1820. Related: Lucently.
Lucia: fem. proper name; see Lucy.
Lucian: masc. proper name, from Latin Lucianus (source also of French Lucien), a derivative of Roman Lucius, from lux (genitive lucis) "light" (see light (n.)). The Hellenistic Greek writer (his name Latinized from Greek Loukianos) was noted as the type of a scoffing wit.
lucid (adj.): 1590s, "bright, shining," from Latin lucidus "light, bright, clear," figuratively "perspicuous, lucid, clear," from lucere "to shine," from lux (genitive lucis) "light," from PIE root *leuk- "to shine, be bright" (see light (n.)). Sense of "easy to understand" first recorded 1786. Lucid interval "period of calm or temporary sanity" (1580s) is from Medieval Latin lucida intervalla (plural), which was common in medieval English legal documents (non est compos mentis, sed gaudet lucidis intervallis). Related: Lucidly; lucidness (1640s).