leopard (n.) Look up leopard at Dictionary.com
late 13c., from Old French lebard, leupart (12c., Modern French léopard), from Late Latin leopardus, literally "lion-pard," from Greek leopardos, from leon "lion" + pardos "male panther," which generally is said to be connected to Sanskrit prdakuh "panther, tiger." The animal was thought in ancient times to be a hybrid of these two species.
Leopold Look up Leopold at Dictionary.com
masc. proper name, from French Léopold, from Old High German Leutpald, Liutbald, literally "bold among the people," from leudi "people" + bald "bold."
leotard (n.) Look up leotard at Dictionary.com
1881, leotards, named for Jules Léotard (1830-1870), popular French trapeze artist, who performed in such a garment.
leper (n.) Look up leper at Dictionary.com
"one afflicted with leprosy," late 14c., from Late Latin lepra, from Greek lepra "leprosy," from fem. of lepros (adj.) "scaly," from leops "a scale," related to lepein "to peel," from lopos "a peel," from PIE root *lep- "to peel, scale" (see leaf (n.)). Originally the word for the disease itself (mid-13c.); because of the -er ending it came to mean "person with leprosy," so leprosy was coined 16c. from adjective leprous.
Lepidoptera (n.) Look up Lepidoptera at Dictionary.com
1773, "insects with four scaly wings," the biological classification that includes butterflies and moths, coined 1735 in Modern Latin by Swedish botanist Carolus Linnaeus (Karl von Linné, 1707-1778) from Greek lepido-, comb. form of lepis (genitive lepidos) "(fish) scale" (related to lepein "to peel;" see leper) + pteron "wing, feather" (see ptero-).
lepidopterist (n.) Look up lepidopterist at Dictionary.com
1826, from Lepidoptera + -ist.
leprechaun (n.) Look up leprechaun at Dictionary.com
c. 1600, from Irish lupracan, metathesis of Old Irish luchorpan literally "a very small body," from lu "little" (from PIE *legwh- "having little weight;" see light (adj.)) + corpan, diminutive of corp "body," from Latin corpus "body" (see corporeal). Commonly spelled lubrican in 17c. English. Leithbragan is Irish folk etymology, from leith "half" + brog "brogue," because the spirit was "supposed to be always employed in making or mending a single shoe."
leprosy (n.) Look up leprosy at Dictionary.com
1530s (earlier lepruse, mid-15c.), from leprous; see leper. First used in Coverdale Bible, where it renders Hebrew cara'ath, which apparently was a comprehensive term for skin diseases. Because of pejorative associations, the use of the word in medical context has been banned by the World Health Organization and replaced by Hansen's disease (1938), named for Norwegian physician Gerhard Henrik Armauer Hansen (1841-1912) who in 1871 discovered the bacillus that causes it.
leprous (adj.) Look up leprous at Dictionary.com
early 13c., leprus, from Old French lepros (Modern French lépreux), from Late Latin leprosus, from Latin lepra "leprosy" (see leper).
lepton (n.) Look up lepton at Dictionary.com
elementary particle of small mass, 1948, from Greek leptos "small, slight, slender, delicate" (from lepein "to peel," from PIE *lep-; see leper) + -on. Also the name of a small coin in ancient Greece, from neuter of leptos
lesbian (adj.) Look up lesbian at Dictionary.com
1590s, "pertaining to the island of Lesbos," from Latin Lesbius, from Greek lesbios "of Lesbos," Greek island in northeastern Aegean Sea (the name originally may have meant "wooded"), home of Sappho, great lyric poet whose erotic and romantic verse embraced women as well as men, hence meaning "relating to homosexual relations between women" (1890; lesbianism in this sense is attested from 1870) and the noun, first recorded 1925.

Her particular association in English with erotic love between women dates to at least 1825, though the words formed from it are later. Before this, the principal figurative use (common in 17c.) was lesbian rule (c. 1600) a mason's rule of lead, of a type used on Lesbos, which could be bent to fit the curves of a molding; hence, "pliant morality or judgment."
And this is the nature of the equitable, a correction of law where it is defective owing to its universality. ... For when the thing is indefinite the rule also is indefinite, like the leaden rule used in making the Lesbian moulding; the rule adapts itself to the shape of the stone and is not rigid, and so too the decree is adapted to the facts. [Aristotle, "Nicomachean Ethics"]
See also tribadism. Greek had a verb lesbiazein "to imitate the Lesbians," which implied "sexual initiative and shamelessness" among women (especially fellatio), but not necessarily female homosexuality.
lesbianism (n.) Look up lesbianism at Dictionary.com
1870, from lesbian + -ism.
lesbo Look up lesbo at Dictionary.com
by 1940, colloquial shortening of lesbian.
lese-majesty (n.) Look up lese-majesty at Dictionary.com
"offense against sovereign authority, treason," 1530s (mid-15c. as an Anglo-French word), from French lèse-majesté, from Latin laesa majestos "violated majesty," from laesus, past participle of laedere "to hurt, injure, damage, offend, insult," of unknown origin.
lesion (n.) Look up lesion at Dictionary.com
early 15c., from Middle French lesion, from Latin laesionem (nominative laesio) "injury," from past participle stem of laedere "to strike, hurt, damage," of unknown origin. Originally with reference to any sort of hurt, whether physical or not.
less Look up less at Dictionary.com
Old English læs (adv.), læssa (adj.), comparative of læs "small;" from Proto-Germanic *lais-izo "smaller" (cognates: Old Saxon, Old Frisian les "less;" Middle Dutch lise "soft, gentle," German leise "soft"), from PIE root *leis- (2) "small" (cognates: Lithuanian liesas "thin"). Formerly also "younger," as a translation of Latin minor, a sense now obsolete except in James the Less. Used as a comparative of little, but not related to it. The noun is Old English læsse.
lessee (n.) Look up lessee at Dictionary.com
"one to whom a lease is given," late 15c., from Anglo-French lesee, Old French lessé, past participle of lesser (Modern French laisser) "to let, leave" (see lease).
lessen (v.) Look up lessen at Dictionary.com
"to become less," c. 1300, from less + -en (1). Related: Lessened; lessening.
lesser (adj.) Look up lesser at Dictionary.com
early 13c., a double comparative, from less + -er (2). Johnson calls it "a barbarous corruption of less, formed by the vulgar from the habit of terminating comparatives in -er." As an adverb from 1590s; now generally poetic or obsolete except in expression lesser-known (1813).
lesson (n.) Look up lesson at Dictionary.com
early 13c., "a reading aloud from the Bible," also "something to be learned by a student," from Old French leçon, from Latin lectionem (nominative lectio) "a reading," noun of action from past participle stem of legere "to read" (see lecture (n.)). Transferred sense of "an occurrence from which something can be learned" is from 1580s.
lessor (n.) Look up lessor at Dictionary.com
"one who grants a lease," late 14c., from Anglo-French lessor (late 13c.), from verb lesser (see lease).
lest (conj.) Look up lest at Dictionary.com
c. 1200, contracted from Middle English phrase les te "less that," from Old English phrase þy læs þe "whereby less that," from þy, instrumental case of demonstrative article þæt "that" + læs (see less) + þe "the." The þy was dropped and the remaining two words contracted into leste.
let (v.) Look up let at Dictionary.com
Old English lætan "to allow to remain; let go, leave, depart from; leave undone; to allow; bequeath," also "to rent" (class VII strong verb; past tense let, past participle læten), from Proto-Germanic *letan (cognates: Old Saxon latan, Old Frisian leta, Dutch laten, German lassen, Gothic letan "to leave, let"), from PIE *le- (2) "to let go, slacken" (cognates: Latin lassus "faint, weary," Lithuanian leisti "to let, to let loose;" see lenient). If that derivation is correct, the primary sense would be "let go through weariness, neglect."

Of blood, from late Old English. To let (something) slip originally (1520s) was a reference to hounds on a leash; figurative use from 1540s. To let (someone) off "allow to go unpunished" is from 1814. To let on "reveal, divulge" is from 1725; to let up "cease, stop" is from 1787. Let alone "not to mention" is from 1812.
let (n.) Look up let at Dictionary.com
"stoppage, obstruction" (obsolete unless in legal contracts), late 12c., from archaic verb letten "to hinder," from Old English lettan "hinder, delay," from Proto-Germanic *latjan (cognates: Old Saxon lettian "to hinder," Old Norse letja "to hold back," Old High German lezzen "to stop, check," Gothic latjan "to hinder, make late," Old English læt "sluggish, slow, late"); see late.
let up (n.) Look up let up at Dictionary.com
"cessation," 1837, from verbal phrase let up "cease, stop" (1787). In Old English the phrase meant "to put ashore."
letch (n.) Look up letch at Dictionary.com
"craving, longing," 1796, perhaps a back-formation from lecher, or from a figurative use of latch (v.) in a secondary sense of "grasp, grasp on to."
letdown (n.) Look up letdown at Dictionary.com
also let-down, "disappointment," 1768, from let (v.) + down (adv.). The verbal phrase is from mid-12c. in a literal sense; figuratively by 1795.
lethal (adj.) Look up lethal at Dictionary.com
1580s, from Late Latin lethalis, alteration of Latin letalis "deadly, fatal," from letum "death," of uncertain origin. Form altered in Late Latin by association with lethes hydor "water of oblivion" in Hades in Greek mythology, from Greek lethe "forgetfulness."
lethality (n.) Look up lethality at Dictionary.com
1650s, from lethal + -ity.
lethargic (adj.) Look up lethargic at Dictionary.com
late 14c., litargik, from Latin lethargicus "affected with lethargy," from Greek lethargikos, from lethargos (see lethargy). Related: Lethargically.
lethargy (n.) Look up lethargy at Dictionary.com
late 14c., litarge, from Old French litargie or directly from Medieval Latin litargia, from Late Latin lethargia, from Greek lethargia "forgetfulness," from lethargos "forgetful," originally "inactive through forgetfulness," from lethe "forgetfulness" (see latent) + argos "idle" (see argon). The form with -th- is from 1590s in English.
Lethe Look up Lethe at Dictionary.com
river of Hades (whose water when drunk caused forgetfulness of the past), from Greek lethe, literally "forgetfulness, oblivion," related to lethargos "forgetful," lathre "secretly, by stealth," lathrios "stealthy," lanthanein "to be hidden." Cognate with Latin latere "to be hidden" (see latent). Related: Lethean.
Letitia Look up Letitia at Dictionary.com
fem. proper name, literally "gladness," from Latin laetitia, from laetus "glad," of unknown origin.
Lett Look up Lett at Dictionary.com
1831, from German Lette, from Old High German liuti "people" (German Leute). The native name is Latvji (see Latvia). Related: Lettic; Lettish.
letter (n.1) Look up letter at Dictionary.com
c. 1200, "graphic symbol, alphabetic sign, written character," from Old French letre (10c., Modern French lettre) "character, letter; missive, note," in plural, "literature, writing, learning," from Latin littera (also litera) "letter of the alphabet," of uncertain origin, perhaps via Etruscan from Greek diphthera "tablet," with change of d- to l- as in lachrymose. In this sense it replaced Old English bocstæf, literally "book staff" (compare German Buchstabe "letter, character," from Old High German buohstab, from Proto-Germanic *bok-staba-m).

Latin littera also meant "a writing, document, record," and in plural litteræ "a letter, epistle," a sense first attested in English early 13c., replacing Old English ærendgewrit, literally "errand-writing." The Latin plural also meant "literature, books," and figuratively "learning, liberal education, schooling" (see letters). School letter in sports, attested by 1908, were said to have been first awarded by University of Chicago football coach Amos Alonzo Stagg. Expression to the letter "precisely" is from 1520s (earlier as after the letter). Letter-perfect is from 1845, originally in theater jargon, in reference to an actor knowing the lines exactly. Letter-press, in reference to matter printed from relief surfaces, is from 1840.
letter (n.2) Look up letter at Dictionary.com
"one who lets" in any sense, c. 1400, agent noun from let (v.).
letter (v.) Look up letter at Dictionary.com
"to write in letters," 1660s, from letter (n.1). Earlier it meant "to instruct" (mid-15c.). Related: Lettered; lettering.
lettered (adj.) Look up lettered at Dictionary.com
"literate," c. 1300, from letter (n.). Meaning "inscribed" is from 1660s.
letterhead (n.) Look up letterhead at Dictionary.com
1868, short for letterheading (1867); from letter (n.1) + head (n.). So called because it was printed at the "head" of the piece of paper.
lettering (n.) Look up lettering at Dictionary.com
1640s, "act of writing;" 1811 as "act of putting letters on something," verbal noun from letter (v.).
letters (n.) Look up letters at Dictionary.com
"the profession of authorship or literature," mid-13c., from plural of letter (n.).
lettuce (n.) Look up lettuce at Dictionary.com
late 13c., probably from Old French laitues, plural of laitue "lettuce," from Latin lactuca "lettuce," from lac (genitive lactis) "milk" (see lactation); so called for the milky juice of the plant.
leu (n.) Look up leu at Dictionary.com
monetary unit of Romania, introduced 1867, literally "lion." Monetary names in the Balkans often translate as "lion" because Dutch gold coins stamped with lions circulated widely in the region in the 17c. and the word for "lion" came to be a word for "money" in some languages in the region.
leukaemia (n.) Look up leukaemia at Dictionary.com
alternative spelling of leukemia.
leukemia (n.) Look up leukemia at Dictionary.com
1851, on model of German Leukämie (1848), coined by R. Virchow from Greek leukos "clear, white" (cognate with Gothic liuhaþ, Old English leoht "light;" see light (n.)) + haima "blood" (see -emia).
leukemic (adj.) Look up leukemic at Dictionary.com
also leukaemic, 1852; see leukemia + -ic.
leukocyte (n.) Look up leukocyte at Dictionary.com
also leucocyte, 1860, via French leucocyte, from Greek leuko-, comb. form of leukos "white" (see light (n.)) + -cyte (see cyto-).
lev (n.) Look up lev at Dictionary.com
monetary unit of Bulgaria, introduced 1881, literally "lion" (see leu).
Levant Look up Levant at Dictionary.com
"Mediterranean lands east of Italy," late 15c., from Middle French levant "the Orient," from present participle of lever "to rise" (from Latin levare "to raise;" see lever). The region so called in reference to the direction of sunrise.
Levantine (adj.) Look up Levantine at Dictionary.com
1640s, from Levant + -ine (1).