( also the Dewey System ) ( abbr DDC )
the most commonly used system for organizing books in public libraries. It was invented by Melvil Dewey (1851–1931), a US librarian. Dewey gave every subject a number between 0 and 999. Every book in a library is given one of these numbers so that books on a particular subject are easy to find. New subjects have been added to Dewey’s original list by using decimal numbers, e.g. 331.1, 331.2, etc.