The Collaborative International Dictionary of English v.0.48:

Library \Li"bra*ry\ (l[imac]"br[asl]*r[y^]), n.; pl. Libraries
   (-r[i^]z). [OE. librairie, F. librairie bookseller's shop,
   book trade, formerly, a library, fr. libraire bookseller, L.
   librarius, from liber book; cf. libraria bookseller's shop,
   librarium bookcase, It. libreria. See Libel.]
   1. A considerable collection of books kept for use, and not
      as merchandise; as, a private library; a public library.
      [1913 Webster]

   2. A building or apartment appropriated for holding such a
      collection of books. --Holland.
      [1913 Webster]

WordNet (r) 3.0 (2006):

library
    n 1: a room where books are kept; "they had brandy in the
         library"
    2: a collection of literary documents or records kept for
       reference or borrowing
    3: a depository built to contain books and other materials for
       reading and study [syn: library, depository library]
    4: (computing) a collection of standard programs and subroutines
       that are stored and available for immediate use [syn:
       library, program library, subroutine library]
    5: a building that houses a collection of books and other
       materials

Moby Thesaurus II by Grady Ward, 1.0:

132 Moby Thesaurus words for "library":
   ALA, American Library Association, Bodleian Library,
   British Museum, Festschrift, Indian reservation,
   Library of Congress, Vatican Library, ana, anthology, aquarium,
   archives, armory, arsenal, atelier, athenaeum, attic, back number,
   bank, basement, bay, bibliotheca, bin, bird sanctuary, body,
   bonded warehouse, book wagon, bookcase, bookery, bookmobile,
   bookroom, box, bunker, buttery, cargo dock, cellar, chest,
   chrestomathy, circulating library, closet, collectanea, collection,
   compilation, conservatory, copy, corpus, crate, crib, cupboard,
   data, depository, depot, dock, drawer, dump, edition, exchequer,
   florilegium, forest preserve, fund, game reserve, glory hole,
   godown, hold, holdings, hutch, impression, issue, lending library,
   library edition, locker, loft, lumber room, lumberyard, magasin,
   magazine, menagerie, museum, national forest, national park,
   number, office, paradise, park, preserve, printing, public library,
   rack, raw data, reading room, rental library, repertory,
   repository, reservation, reserve, reservoir, rick, sail loft,
   sanctuary, school edition, series, set, shelf, stack, stack room,
   stacks, state forest, stock room, storage, store, storehouse,
   storeroom, studio, study, supply base, supply depot, tank,
   trade book, trade edition, treasure, treasure house, treasure room,
   treasury, vat, vault, volume, warehouse, wilderness preserve,
   wildlife preserve, wine cellar, workroom, zoo



The Free On-line Dictionary of Computing (30 December 2018):

library

    A collection of subroutines and
   functions stored in one or more files, usually in compiled
   form, for linking with other programs.  Libraries are one of
   the earliest forms of organised code reuse.  They are often
   supplied by the operating system or software development
   environment developer to be used in many different programs.
   The routines in a library may be general purpose or designed
   for some specific function such as three dimensional animated
   graphics.

   Libraries are linked with the user's program to form a
   complete executable.  The linking may be static linking
   or, in some systems, dynamic linking.

   (1998-11-21)