Library of Congress classification - A system of organizing materials in the library by subject so that all the resources on the same general topic are on the shelves together. This type of organization allows you to browse the shelves for more information. 
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Special vocabulary, or subject headings that can be used to find information in a card catalog or online catalog.

Location - Where the physical item is housed. In McQuade's Evergreen catalog, Location is given to the left of the call number in the item's record e.g. Stacks (2nd).