The only free and comprehensive online etymological dictionary of the Spanish language
legrar (Verb) (med.) "to scrape the fibrous membrane of a bone;" "to scrape the lining of a uterus"

16th cent. From legra.
lejos (Adjective) "far"

13th cent. From Latin laxius "wider," "looser," from laxus "wide." See laja for continued etymology.

Romance: Western Vulgar Latin: Italian lasso ; Eastern Vulgar Latin: Romanian lax
lengua f. (Noun) "tongue;" "language"

12th cent. From Latin lingua 'id.' Old Latin dingua. The change from d- to l- was a taboo distortion and from contamination from lingere "to lick." From Proto-Italic *dn̥χwā- "tongue." From Proto-Indo-European *dnǵh-u̯h2- 'id.'

Romance: Western Vulgar Latin: Asturian llingua, Portuguese língua, Galician lingua, Catalan llengua, French langue, Italian lingua; Eastern Vulgar Latin: Aromanian limbã, Romanian limbã; Sardinian:limba

Italic: Oscan fancua "tongues"

Indo-European: Celtic: Old Irish tengae "tongue," Old Welsh tauawt 'id.,' Middle Breton teaut 'id.,' Old Cornish tauot 'id.;' Germanic: Gothic tuggo "tongue," Old Norse tunga 'id.,' Old High German zunga 'id.,' Old Saxon tunga, Old English tunge (English tongue); Balto-Slavic: Old Church Slavonic językъ "tongue," Russian jazýk 'id.,' Old Prussian insuwis 'id.,' Lithuanian liežuvìs 'id.;' Armenian: lezow "tongue;" Indo-Iranian: Sanskrit jihvā- "tongue," Avestan hizuuā- 'id.;' Tocharian: A käntu "tongue," B kantwo 'id.'
leve (Adjective) (weight) "light"

15th cent. From Latin levis 'id.' From Proto-Italic *leχu- 'id.' From Proto-Indo-European *h1legwh-u̯- 'id.' From the root *h1legwh- "to be spry."

Romance: Western Vulgar Latin: Portuguese leve, Catalan lleu, French liège, Italian lieve

Indo-European: Celtic: Old Irish laigiu "lighter," Middle Welsh llaw "small," Old Breton lau 'id.;' Germanic: Gothic leihts "light," Old Norse léttr 'id.,' Old High German līht 'id.,' Old English līht (English light); Balto-Slavic: Old Church Slavonic lьgъkъ "light," Russian lëgkij 'id.,' Slovene lagȃk 'id.,' Lithuanian leñgvas 'id.;' Albanian: lehtë "light;" Hellenic: Ancient Greek ἐλαχύς (elakhys) "small;" Indo-Iranian: Sanskrit raghú- "fast," Young Avestan rəuuī- 'id.;' Tocharian: B laṅkutse "light"
ley f. (Noun) "law"

12th cent. From Latin legem 'id.' accusative form of lex. From Proto-Italic *lēg- 'id.' Of uncertain origin.

Romance: Western Vulgar Latin: Asturian llei, Portuguese lei, Galician lei, Catalan llei, French loi, Italian legge; Eastern Vulgar Latin: Aromanian leadzi, Romanian lege

Italic: Oscan ligus "by the law," Marrucinian lixs "law"
libertad f. (Noun) "liberty"

13th cent. From libertas 'id.,' from liber "free" and -tas (see libre and -tad respectively).

Romance: Western Vulgar Latin: Portuguese liberdade, Galician liberdade, Catalan llibretat, French liberté, Italian libertà; Eastern Vulgar Latin: Romanian libertate

"Although the opposition “free/slave” is common to all Indo-European peoples, a common designation of the notion of “liberty” is unknown." ~ E. Benveniste, Indo-European Language and Society (1973)
libra f. (Noun) "pound"

13th cent. From Latin libra "pound," "balance." The meaning of a pound is probably the original sense of the word. From Proto-Italic *leiþra- "pound," and perhaps "coin." Of unknown origin. Probably borrowed from another language.

Romance: Western Vulgar Latin: Portuguese libra, Galician libra, French livre, Italian libra; Eastern Vulgar Latin:livră

Hellenic: Ancient Greek λίτρα (lítra) "Sicilian coin equivalent to 50 drachmes," "pound" (as the Proto-Hellenic form was *līþrā, it looks like the word was borrowed from Proto-Italic *leiþra-; however, one could just as easily assume both *līþrā and *leiþra- were borrowed from a mutual source in Sicily)
libre (Adjective) "free"

Early 13th cent. From Latin liber 'id.' From Proto-Italic *leuþ-ero- 'id.' From Proto-Indo-European *h1leu̯dh-ero- "free" but literally "one of the people" in the sense that the people are assumed to be free, unenslaved individuals. From the root noun *h1leu̯dh- "people," taken directly from an older root verb *h1leu̯dh- "to grow."

Italic: Oscan lúvfreis "of the freeman," Paelignian loufir "freeman," Faliscan loferta "freewoman," Venetic louderobos "for the children"

Indo-European: Germanic: Old Norse lýðr "people," Old High German liut 'id.,' Old Saxon liud 'id.' Old English lēod (English lede); Balto-Slavic: Old Church Slavonic ljudьje "people," Russian ljúdi 'id.,' Polish ludzie, Slovene ljudję̑ 'id.,' Lithuanian liáudis "lower people," Latvian ļaudis 'id.;' Hellenic: Ancient Greek ἐλεύθερος (eleytheros) "free"
libro m. (Noun) "book"

12th cent. From Latin librum, accusative of liber "book," but originally "tree bark." From Proto-Italic *lufro- 'id.' From Proto-Indo-European *lu̯bh-ro- "leaf." From *leu̯bh- "to peel."

Indo-European: Celtic: Old Irish luib "herb," Middle Welsh luibh 'id.,' Old Breton -lub 'id.,' Cornish lowarth "garden;" Germanic: Gothic lubja-leis "witchcraft," laub "leaf," Old Norse lýf "medicinal herbs," lauf "leaf," Old High German loub "leaf," Old Saxon lōf 'id.,' Old English lēaf (English leaf), lybb "poison;" Balto-Slavic: Russian lob "forehead," Czech leb "skull," Old Prussian lubbo "plank," Lithuanian lubà 'id.,' Latvian luba 'id.;' Albanian: labë "rind;"
líder m. (Noun) "leader"

Borrowed from English leader. Old English lǣdere 'id.' From the verb lēad "to lead." From Proto-Germanic *laidjan- 'id.' From Proto-Indo-European *loi̯t-ei̯e- 'id.,' an ablaut derivation of *lei̯t- "to pass."

Italic: Latin litus "coast"

Germanic: North Germanic: Old Norse leiða; West Germanic: Old High German leiten, Old Saxon lēdian, Old English lǣdan (English to lead)

Indo-European: Hellenic: Ancient Greek λοίτη (loíte) "tomb;" Indo-Iranian: Young Avestan iriϑiieiti "to die;" Tocharian: A litā- "to pass on," B litā- 'id.'