low-grade (adj.) Look up low-grade at Dictionary.com
1867, originally in mining, with reference to ores, from low (adj.) + grade (n.).
low-life (adj.) Look up low-life at Dictionary.com
"disreputable, vulgar," 1794, from low (adj.) + life; as a noun, "coarse, no-good person" it is recorded from 1911. Also lowlife.
low-profile (adj.) Look up low-profile at Dictionary.com
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.) Look up lowboy at Dictionary.com
"chest of drawers on short legs," 1891, a hybrid from low (adj.) + French bois "wood" (see bush).
lowbrow (n.) Look up lowbrow at Dictionary.com
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) Look up lower at Dictionary.com
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) Look up lower at Dictionary.com
"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.) Look up lower at Dictionary.com
c. 1200, lahre, comparative of lah (see low (adj.)).
lower-case (adj.) Look up lower-case at Dictionary.com
also lowercase, 1680s; see lower (adj.) + case (n.2).
lowercase (v.) Look up lowercase at Dictionary.com
"to set (text) in lower-case type," 1911, from lower-case (adj.). Related: Lowercased; lowercasing.
lowermost Look up lowermost at Dictionary.com
1560s, from lower (adj.) + -most.
lowest (adj.) Look up lowest at Dictionary.com
c. 1200, laghesst, superlative of lah (see low (adj.)).
Lowestoft (n.) Look up Lowestoft at Dictionary.com
type of porcelain, named for a town in Suffolk where it was made from 1757.
lowing (n.) Look up lowing at Dictionary.com
early 13c., verbal noun from low (v.).
lowland (n.) Look up lowland at Dictionary.com
c. 1500, originally with reference to Scotland, from low (adj.) + land (n.). Related: Lowlander.
lowliness (n.) Look up lowliness at Dictionary.com
early 15c., from lowly + -ness.
lowly Look up lowly at Dictionary.com
c. 1300 (adv.); late 14c. (adj.) "humble," from low (adj.) + -ly.
lowness (n.) Look up lowness at Dictionary.com
early 13c., from low (adj.) + -ness.
lox (n.) Look up lox at Dictionary.com
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- Look up loxo- at Dictionary.com
word-forming element meaning "oblique," before vowels lox-, from Greek loxos "slanting, crosswise, oblique." E.g. loxodromics "art of oblique sailing."
loyal (adj.) Look up loyal at Dictionary.com
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.) Look up loyalism at Dictionary.com
1812, from loyal + -ism.
loyalist (n.) Look up loyalist at Dictionary.com
1680s, from loyal + -ist. Meaning different persons in different times and places.
loyally (adv.) Look up loyally at Dictionary.com
1570s, from loyal + -ly (2).
loyalty (n.) Look up loyalty at Dictionary.com
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.) Look up lozenge at Dictionary.com
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 Look up LP at Dictionary.com
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 Look up LSD at Dictionary.com
"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. Look up Ltd. at Dictionary.com
abbreviation of limited, attested by 1900.
luau (n.) Look up luau at Dictionary.com
Hawaiian party or feast, 1853, from Hawaiian lu'au, literally "young taro tops," which were served at outdoor feasts.
lubber (n.) Look up lubber at Dictionary.com
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.) Look up lubber at Dictionary.com
1520s, from lubber (n.). Related: Lubbered; lubbering.
lubberly (adj.) Look up lubberly at Dictionary.com
1570s, from lubber (n.) + -ly (1).
lube Look up lube at Dictionary.com
1934, colloquial shortening of lubrication. As a verb (short for lubricate) recorded from 1961.
Lubish Look up Lubish at Dictionary.com
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.) Look up lubric at Dictionary.com
"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.) Look up lubricant at Dictionary.com
1828, probably from lubricant (adj.), or from Latin lubricantem.
lubricant (adj.) Look up lubricant at Dictionary.com
"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.) Look up lubricate at Dictionary.com
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.) Look up lubrication at Dictionary.com
1640s, "act of lubricating," noun of action from lubricate (v.). Earlier were lubifraction (1540s).
lubricity (n.) Look up lubricity at Dictionary.com
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.) Look up lubricous at Dictionary.com
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.) Look up lubritorium at Dictionary.com
"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.) Look up lucency at Dictionary.com
1650s, from lucent + -cy. Lucence is from late 15c.
lucent (adj.) Look up lucent at Dictionary.com
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 Look up Lucia at Dictionary.com
fem. proper name; see Lucy.
Lucian Look up Lucian at Dictionary.com
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.) Look up lucid at Dictionary.com
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).
lucidity (n.) Look up lucidity at Dictionary.com
1650s, "brightness," from French lucidité, from Late Latin luciditas, from lucidus (see lucid). Meaning "intellectual clarity" attested by 1851.
Lucifer Look up Lucifer at Dictionary.com
Old English Lucifer "Satan," also "morning star," from Latin Lucifer "morning star," literally "light-bringing," from lux (genitive lucis) "light" (see light (n.)) + ferre "carry" (see infer).

Belief that it was the proper name of Satan began with its use in Bible to translate Greek Phosphoros, which translates Hebrew Helel ben Shahar in Isaiah xiv:12 -- "How art thou fallen from heaven, O Lucifer, son of the morning!" [KJV] Because of the mention of a fall from Heaven, the verse was interpreted by Christians as a reference to Satan, even though it is literally a reference to the King of Babylon (see Isaiah xiv:4).

Lucifer match "friction match" is from 1831. Adjectival forms include Luciferian, Luciferine, Luciferous. There was a noted Bishop Lucifer of Cagliari in Sardinia in the 4th century, regarded locally as a saint.