Definition of Dewey Decimal Classification in US English:

Dewey Decimal Classification

(also Dewey system)


  • An internationally applied decimal system of library classification which uses a three-figure code from 000 to 999 to represent the major branches of knowledge, and allows finer classification to be made by the addition of further figures after a decimal point.

    • ‘Based on such an analysis, Orom has been able to discern a dominant view in, for example, the Library of Congress and Dewey decimal classifications.’
    • ‘It's like having a librarian who doesn't read books or understand the Dewey system categorising your reading and telling you what you can read based on their worthless biases.’
    • ‘This is a series of quizzes about how to use the Dewey system developed by the University of Texas at Austin.’
    • ‘The Open Directory is supposed to be based around the Dewey system used for libraries, I believe.’
    • ‘After reading about the LC System of Classification, have learner discuss the differences and similarities between LC and Dewey systems.’


Late 19th century: named after Melvil Dewey (1851–1931), American librarian.


Dewey Decimal Classification

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