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Three digits, a decimal point and further digits.
Also known as: DDC number, Dewey number, Dewey Decimal Classification, Three digits with a decimal
A Dewey number classifies a subject in three digits with decimal subdivision, and its structure encodes hierarchy — 500 is science, 510 mathematics, 516 geometry. Its historical treatment of religion and of non-Western cultures is documented as skewed, and revisions have addressed but not removed the imbalance.
Denotes a Dewey Decimal Classification number: three digits dividing knowledge into ten classes, with decimal subdivision for specificity.
Contexts: History
Encodes hierarchy positionally, so a longer number is a narrower subject within the one its prefix names.
Contexts: History
Allocates disproportionate space to Christianity within its religion class and to Europe and North America within its geographic tables, an imbalance documented since the system's creation and addressed by revision without being removed.
The imbalance is a documented and much-discussed property of the scheme rather than a contested claim. Successive editions have expanded coverage of other religions and regions; the underlying allocation of number space remains uneven.
Contexts: History
Is used by most public and school libraries worldwide, in contrast to the Library of Congress system used by most academic libraries in North America.
Contexts: History
Three digits followed by a decimal point and further digits, printed on a spine label.