Library of Congress Card Number The number assigned to an item by the Library of Congress, which is also a depository library. Used to order catalog cards from LC and to search the OCLC database.
Library of Congress Call Number. A sequence of numbers used to identify materials.
Established in 1901, a numbering system assigned by the Library of Congress, this number is used by libraries throughout the United States to identify each book in their stacks. Every book that is expected to sell to libraries must have a Library of Congress Catalog Number.