Library
late Middle English: via Old French from Latin libraria ‘bookshop’, feminine (used as a noun) of librarius ‘relating to books’, from liber, libr- ‘book’.
wiktionary
Middle English librarie, from Anglo-Norman librarie, from Old French librairie, from Latin librarium(“bookcase, chest for books”), from librarius(“concerning books”), from liber(“the inner bark of trees; paper, parchment, book”), probably derived from a Proto-Indo-European base *leub(ʰ)-(“to strip, to peel”). Displaced native Middle English bochus, bochous(literally “book house”), from Old English bōchūs.
Romance cognates often mean “bookshop” instead: French librairie, Italian libreria, Spanish librería, Romanian librărie and Portuguese livraria. This is a relatively recent innovation (16th century in French), which ended up displacing the earlier sense.
etymonline
library (n.)
place for books, late 14c., from Anglo-French librarie, Old French librairie, librarie "collection of books; bookseller's shop" (14c.), from Latin librarium "book-case, chest for books," and libraria "a bookseller's shop," in Medieval Latin "a library," noun uses of the neuter and fem., respectively, of librarius "concerning books," from Latin librarium "chest for books," from liber (genitive libri) "book, paper, parchment."
Latin liber (from Proto-Italic *lufro-) was originally "the inner bark of trees," and perhaps is from PIE *lubh-ro- "leaf, rind," a derivative of the PIE root *leub(h)- "to strip, to peel" (see leaf (n.)). Comparing Albanian labë "rind, cork;" Lithuanian luobas "bast," Latvian luobas "peel," Russian lub "bast," de Vaan writes that, "for want of a better alternative, we may surmise that liber is cognate with *lubh- and goes back to a PIE word or a European word 'leaf, rind.'"
The equivalent word in most Romance languages survives only in the sense "bookseller's shop" (French libraire, Italian libraria). Old English had bochord, literally "book hoard." As an adjective, Blount (1656) has librarious.
