lead-up (n.) Look up lead-up at Dictionary.com
1917, from lead (v.1) + up (adv.).
leaden (adj.) Look up leaden at Dictionary.com
"made of lead," Old English leaden, from lead (n.1) + -en (2). The figurative sense of "heavy, oppressive, dull" is attested by 1570s. Related: Leadenly; leadenness.
leader (n.) Look up leader at Dictionary.com
Old English lædere "one who leads," agent noun from lædan (see lead (v.)). As a title for the head of an authoritarian state, from 1918 (translating führer, Duce, caudillo, etc.). Meaning "writing or statement meant to begin a discussion or debate" is late 13c.; in modern use often short for leading article (1807) "opinion piece in a British newspaper" (leader in this sense attested from 1837).
leaderless (adj.) Look up leaderless at Dictionary.com
1590s, from leader (n.1) + -less. Related: Leaderlessly; leaderlessness.
leadership (n.) Look up leadership at Dictionary.com
1821, "position of a leader," from leader + -ship. Sense extended by late 19c. to "characteristics necessary to be a leader."
leading (n.1) Look up leading at Dictionary.com
"lead work; lead covering or frame of lead," mid-15c., from lead (n.1).
leading (n.2) Look up leading at Dictionary.com
mid-13c., "a bringing by force," from present participle of lead (v.1). Meaning "direction, guidance" is from late 14c. As an adjective, "directing, guiding."
leaf (v.) Look up leaf at Dictionary.com
"to turn over (the pages of a book)," 1660s, from leaf (n.). The notion of a book page also is in the phrase to turn over a (new) leaf (1570s). Related: Leafed; leaved; leafing.
leaf (n.) Look up leaf at Dictionary.com
Old English leaf "leaf of a plant; page of a book," from Proto-Germanic *laubaz (cognates: Old Saxon lof, Old Norse lauf, Old Frisian laf, Dutch loof, Old High German loub, German Laub "foliage, leaves," Gothic lauf), perhaps from PIE *leup- "to peel off, break off" (cognates: Lithuanian luobas, Old Church Slavonic lubu "bark, rind"). Extended 15c. to very thin sheets of metal (especially gold). Meaning "hinged flap on the side of a table" is from 1550s.
leafless (adj.) Look up leafless at Dictionary.com
1580s, from leaf (n.) + -less.
leaflet (n.) Look up leaflet at Dictionary.com
1787 as a term in botany; 1867 as a term in printing and publication; diminutive of leaf (n.) with -let.
A newspaperman asked the British authorities for a copy of the leaflets distributed in Germany by British airplanes. According to the London Daily Herald, his request was refused with the following answer: "Copies are not given out, as they might fall into enemy hands." ["The Living Age" magazine, Sept. 1939-Feb. 1940]
leafy (adj.) Look up leafy at Dictionary.com
1550s, from leaf (n.) + -y (2). Related: Leafily; leafiness.
league (n.1) Look up league at Dictionary.com
"alliance," mid-15c., ligg, from Middle French ligue "confederacy, league" (15c.), from Italian lega, from legare "to tie, to bind," from Latin ligare "to bind" (see ligament). Originally among nations, subsequently extended to political associations (1846) and sports associations (1879). League of Nations first attested 1917 (created 1919).
league (n.2) Look up league at Dictionary.com
distance of about three miles, late 14c., ultimately from Late Latin leuga (source also of French lieue, Spanish legua, Italian lega), said by Roman writers to be from Gaulish. A vague measure (perhaps originally an hour's hike) never in official use in England, where it is recorded more often in poetic than in practical writing.
league (v.) Look up league at Dictionary.com
"to form a league," 1610s, from league (n.1). Related: Leagued; leaguing.
leak (n.) Look up leak at Dictionary.com
late 15c., from leak (v.) or Old Norse cognate leki. Sense of "revelation of secret information" is from 1950. Meaning "act of urination" is attested from 1934 ("Tropic of Cancer"); but the verb meaning "to piss" is from 1590s: "Why, you will allow vs ne're a Iourden, and then we leake in your Chimney." ["I Hen. IV," II.i.22]
leak (v.) Look up leak at Dictionary.com
"to let water in or out" [Johnson], late 14c., from Middle Dutch leken "to drip, to leak," or from Old Norse leka, both of them related to Old English leccan "to moisten" (which did not survive into Middle English), all from Proto-Germanic *lek- "deficiency" (source also of Old High German lecchen "to become dry," German lechzen "to be parched with thirst"), from PIE root *leg- (2) "to dribble, trickle." The figurative meaning "come to be known in spite of efforts at concealment" dates from at least 1832; transitive sense first recorded 1859. Related: Leaked; leaking.
leakage (n.) Look up leakage at Dictionary.com
late 15c., from leak (v.) + -age.
leaky (adj.) Look up leaky at Dictionary.com
mid-15c., from leak (n.) + -y (2). Related: Leakiness.
leal (adj.) Look up leal at Dictionary.com
"loyal, faithful, honest, true," c. 1300, lele, surviving from Middle English as Northern English and Scottish form of loyal. The Land of the leal is Heaven, not Scotland.
lean (v.) Look up lean at Dictionary.com
c. 1200, from Old English hleonian "to bend, recline, lie down, rest," from Proto-Germanic *khlinen (cognates: Old Saxon hlinon, Old Frisian lena, Middle Dutch lenen, Dutch leunen, Old High German hlinen, German lehnen "to lean"), from PIE root *klei- "to lean, to incline" (cognates: Sanskrit srayati "leans," sritah "leaning;" Old Persian cay "to lean;" Lithuanian slyti "to slope," slieti "to lean;" Latin clinare "to lean, bend," clivus "declivity," inclinare "cause to bend," declinare "bend down, turn aside;" Greek klinein "to cause to slope, slant, incline;" Old Irish cloin "crooked, wrong;" Middle Irish cle, Welsh cledd "left," literally "slanting;" Welsh go-gledd "north," literally "left" -- for similar sense evolution, see Yemen, Benjamin, southpaw).

Meaning "to incline the body against something for support" is mid-13c. Figurative sense of "to trust for support" is from early 13c. Sense of "to lean toward mentally, to favor" is from late 14c. Related: Leaned; leaning. Colloquial lean on "put pressure on" (someone) is first recorded 1960.
lean (adj.) Look up lean at Dictionary.com
"thin, spare, with little flesh or fat," c. 1200, from Old English hlæne "lean, thin," possibly from hlænan "cause to lean or bend," from Proto-Germanic *khlainijan, which would connect it to Old English hleonian (see lean (v.)). But perhaps rather, according to OED, from a PIE *qloinio- (with cognates in Lithuanian klynas "scrap, fragment," Lettish kleins "feeble"). Extended and figurative senses from early 14c. The noun meaning "lean animals or persons" is from c. 1200, from the adjective.
lean (n.) Look up lean at Dictionary.com
"action or state of leaning," 1776, from lean (v.).
lean-to (n.) Look up lean-to at Dictionary.com
"building whose rafters pitch against another building or wall," mid-15c., from lean (v.) + to.
Leander Look up Leander at Dictionary.com
youth of Abydos, lover of Hero, who swam nightly across the Hellespont to visit her, from Greek Leiandros, literally "lion-man," from leon "lion" + aner (genitive andros) "man" (see anthropo-).
leanness (n.) Look up leanness at Dictionary.com
Old English hlænnesse; see lean (adj.) + -ness.
leap (v.) Look up leap at Dictionary.com
c. 1200, from Old English hleapan "to jump, run, leap" (class VII strong verb; past tense hleop, past participle hleapen), from Proto-Germanic *hlaupan (cognates: Old Saxon hlopan, Old Norse hlaupa, Old Frisian hlapa, Dutch lopen, Old High German hlouffan, German laufen "to run," Gothic us-hlaupan "to jump up"), of uncertain origin, with no known cognates beyond Germanic. Leap-frog, the children's game, is attested by that name from 1590s; figurative use by 1704.
First loke and aftirward lepe [proverb recorded from mid-15c.]
Related: Leaped; leaping.
leap (n.) Look up leap at Dictionary.com
c. 1200, from Old English hliep, hlyp (West Saxon), *hlep (Mercian, Northumbrian) "a leap, bound, spring, sudden movement; thing to leap from;" common Germanic (cognates: Old Frisian hlep, Dutch loop, Old High German hlouf, German lauf); from the root of leap (v.). Leaps has been paired with bounds since at least 1720.
leap year (n.) Look up leap year at Dictionary.com
late 14c., from leap (v.) + year. So called from its causing fixed festival days, which normally advance one weekday per year, to "leap" ahead one day in the week.
learn (v.) Look up learn at Dictionary.com
Old English leornian "to get knowledge, be cultivated, study, read, think about," from Proto-Germanic *liznojan (cognates: Old Frisian lernia, Middle Dutch leeren, Dutch leren, Old High German lernen, German lernen "to learn," Gothic lais "I know"), with a base sense of "to follow or find the track," from PIE *leis- (1) "track, furrow." Related to German Gleis "track," and to Old English læst "sole of the foot" (see last (n.)).

The transitive sense (He learned me how to read), now vulgar, was acceptable from c. 1200 until early 19c., from Old English læran "to teach" (cognate with Dutch leren, German lehren "to teach," literally "to make known;" see lore), and is preserved in past participle adjective learned "having knowledge gained by study." Related: Learning.
learnable (adj.) Look up learnable at Dictionary.com
1620s, from learn + -able.
learned (adj.) Look up learned at Dictionary.com
"having knowledge gained by study," mid-14c., past participle adjective from learn (v.) in former transitive sense. Related: Learnedly; learnedness.
learning (n.) Look up learning at Dictionary.com
Old English leornung "learning, study," from leornian (see learn). Learning curve attested by 1907.
lease (n.) Look up lease at Dictionary.com
late 14c., "legal contract conveying property, usually for a fixed period of time and with a fixed compensation," from Anglo-French les (late 13c.), from lesser "to let, let go," from Old French laissier "to let, allow, permit; bequeath, leave," from Latin laxare "loosen, open, make wide," from laxus "loose" (see lax). Medial -x- in Latin tends to become -ss- or -s- in French (compare cuisse from coxa). Modern French equivalent legs is altered by erroneous derivation from Latin legatum "bequest, legacy."
lease (v.) Look up lease at Dictionary.com
late 15c., "to take a lease," from Anglo-French lesser, Old French laissier "to let, leave" (see lease (n.). Related: Leased; leasing. Lessor, lessee in contract language preserves the Anglo-French form.
leash (v.) Look up leash at Dictionary.com
"to attach to or with a leash," 1590s, from leash (n.). Related: Leashed; leashing.
leash (n.) Look up leash at Dictionary.com
"thong for holding a dog or hound," c. 1300, from Old French laisse "hound's leash," from laissier "loosen," from Latin laxare, from laxus "loose" (see lax). Figurative sense attested from early 15c. The meaning "a set of three" is from early 14c., originally in sporting language.
least (adj.) Look up least at Dictionary.com
Old English læst, earlier læsest "smallest" (superlative of lytel "small"), from Proto-Germanic superlative *laisistaz (see less). Qualifying phrase at least is Middle English æt læstan. As a noun, from early 12c.; as an adverb, c. 1200.
leastways Look up leastways at Dictionary.com
1825, colloquial, from least + way (n.). Regarded as vulgar, but simply a one-word form of Chaucer's leest weye (late 14c.).
leather (n.) Look up leather at Dictionary.com
Old English leðer (in compounds only) "hide, skin, leather," from Proto-Germanic *lethran (cognates: Old Norse leðr, Old Frisian lether, Old Saxon lethar, Middle Dutch, Dutch leder, Old High German ledar, German leder), from PIE *letro- "leather" (cognates: Old Irish lethar, Welsh lledr, Breton lezr). As an adjective from early 14c.; it acquired a secondary sense of "sado-masochistic" 1980s, having achieved that status in homosexual jargon in the 1970s.
leathern (adj.) Look up leathern at Dictionary.com
Old English leðren; see leather + -en (2).
leatherneck (n.) Look up leatherneck at Dictionary.com
"U.S. Marine," 1914, Navy slang, from leather + neck (n.). So called for the leather collars of their early uniforms; earlier in British use (1890) as a sailor's term for a soldier.
leathery (adj.) Look up leathery at Dictionary.com
1550s, from leather + -y (2). Related: Leatheriness.
leave (v.) Look up leave at Dictionary.com
Old English læfan "to let remain; remain; have left; bequeath," from Proto-Germanic *laibijan (cognates: Old Frisian leva "to leave," Old Saxon farlebid "left over"), causative of *liban "remain," (source of Old English belifan, German bleiben, Gothic bileiban "to remain"), from root *laf- "remnant, what remains," from PIE *leip- "to stick, adhere;" also "fat."

The Germanic root has only the sense "remain, continue," which also is in Greek lipares "persevering, importunate." But this usually is regarded as a development from the primary PIE sense of "adhere, be sticky" (compare Lithuanian lipti, Old Church Slavonic lipet "to adhere," Greek lipos "grease," Sanskrit rip-/lip- "to smear, adhere to." Seemingly contradictory meaning of "depart" (early 13c.) comes from notion of "to leave behind" (as in to leave the earth "to die;" to leave the field "retreat").
leave (n.) Look up leave at Dictionary.com
"permission," Old English leafe "leave, permission, license," dative and accusative of leaf "permission," from Proto-Germanic *lauba (cognates: Old Norse leyfi "permission," Old Saxon orlof, Old Frisian orlof, German Urlaub "leave of absence"), from PIE *leubh- "to care, desire, love, approve" (see love (n.)). Cognate with Old English lief "dear," the original idea being "approval resulting from pleasure." Compare love, believe. In military sense, it is attested from 1771.
leave-taking (n.) Look up leave-taking at Dictionary.com
late 14c., from leave (n.) + present participle of take (v.).
leaved (adj.) Look up leaved at Dictionary.com
"having leaves," past participle adjective from verb leave "to put forth leaves," mid-13c., from leaf (n.).
leaven (n.) Look up leaven at Dictionary.com
mid-14c., from Old French levain "leaven, sourdough" (12c.), from Latin levamen "alleviation, mitigation," but used in Vulgar Latin in its literal sense of "a means of lifting, something that raises," from levare "to raise" (see lever). Figurative use from late 14c.
leaven (v.) Look up leaven at Dictionary.com
c. 1400, from leaven (n.). Related: Leavened; leavening.
Lebanese Look up Lebanese at Dictionary.com
1860, from Lebanon + -ese.