1. 1. A place in which literary and artistic materials, such as books, periodicals, newspapers, pamphlets, prints, records, and tapes, are kept for reading, reference, or lending.
   2. A collection of such materials, especially when systematically arranged.
   3. A room in a private home for such a collection.
   4. An institution or foundation maintaining such a collection.
2. A commercial establishment that lends books for a fee.
3. A series or set of books issued by a publisher.
4. A collection of recorded data or tapes arranged for ease of use.
5. A set of things similar to a library in appearance, function, or organization: a library of computer programs.
6. Genetics. A collection of cloned DNA sequences whose location and identity can be established by mapping the genome of a particular organism.

[Middle English librarie, from Anglo-Norman, from Latin librārium, bookcase, from neuter of librārius, of books, from liber, libr-, book.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.