Middle English logge, mid-13c. in surnames and place names; late 13c. as "small building or hut," from Old French loge "arbor, covered walk; hut, cabin, grandstand at a tournament" (12c.), from Frankish *laubja "shelter" (cognate with Old High German louba "porch, gallery," German Laube "bower, arbor"), from Proto-Germanic *laubja- "shelter." On a widespread guess (backed by Watkins, OED) this likely originally meant "shelter of foliage," or "roof made from bark," and is from the same PIE root as leaf (n.).

Modern spelling is from c. 1500. The specific sense "hunter's cabin" is first recorded late 14c. Sense of "local branch of a society" is first recorded 1680s, of Freemasons, from an earlier use of lodge as "workshop of a group of masons" (mid-14c.). In the New World the word was used of certain American Indian buildings (1805), hence lodge-pole (1805) and lodge-pole pine (1859).

Old English leaf "leaf of a plant, foliage; page of a book, sheet of paper," from Proto-Germanic *lauba- (source also of Old Saxon lof, Old Norse lauf, Old Frisian laf, Dutch loof, Old High German loub, German Laub "foliage, leaves," Gothic laufs "leaf, foliage"), perhaps from PIE *leub(h)- "to peel off, strip or break off" ((source also of Old Irish luib, "herb," lub-gort "garden;" Albanian labë "rind, cork;" Lithuanian luba "plank, board;" Russian lob "forehead, brow," Czech leb "skull;" Lithuanian luobas "bast," Latvian luobas "peel," Russian lub "bast;" Old Norse lyf "medicinal herbs," Old English lybb "poison; magic").

Related to lodge and lobby; for another PIE root see folio. Extended late 14c. to very thin sheets of metal (especially gold). Compare Lithuanian lapas "leaf," from a root also in Greek lepos "bark," lepein "to peel off." Also applied to flat and relatively broad surfaces, especially of flexible or mounted attachments; meaning "hinged flap on the side of a table" is from 1550s. To turn over a (new) leaf (1590s; 1570s as turn the leaf) "begin a new and better course of life" is a reference to the book sense. Among insects, leaf-hopper is from 1847; leaf-cutter from 1816.

1863, American English, from lobby (n.) in the political sense + -ist.

[A] strong lobbyist will permit himself to lose heavily at the poker-table, under the assumption that the great Congressman who wins the stake will look leniently upon the little appropriation he means to ask for. [George A. Townsend, "Events at the National Capital and the Campaign of 1876," Hartford, Conn., 1876]

also louvre, early 14c., "domed turret-like structure atop a building to disperse smoke and admit light," from Old French lovier, a word of uncertain origin. One theory [OED, Barnhart] connects it to Medieval Latin *lodarium, which might be from a Germanic source (compare Old High German louba "upper room, roof;" see lobby). Skeat and Klein's sources suggest it is from French l'ouvert, literally "the open place," from le, definite article, + past participle of ouvrir "to open." Century Dictionary finds this "quite untenable."

Meaning "overlapping strips in a window" (to let in air but keep out rain) first recorded 1550s. The form has been influenced by apparently unrelated French Louvre, the name of the palace in Paris, which is said to be so named because its builder, Philip Augustus, intended it as a wolf kennel. Related: Louvered, louvred.