n.A system for organizing materials into categories based on a systematic combination of mutually exclusive and collectively exhaustive characteristics of the materials (facets) and displaying the characteristics in a manner that shows their relationships.
Wynar and Taylor 1992, p. 320 A faceted classification differs from a traditional one in that it does not assign fixed slots to subjects in sequence, but uses clearly defined, mutually exclusive, and collectively exhaustive aspects, properties, or characteristics of a class or specific subject. Such aspects, properties, or characteristics are called facets of a class or subject, a term introduced into classification theory and given this new meaning by the Indian librarian and classificationist S. R. Ranganathan and first used in his Colon Classification in the early 1930s. Although the term was then new to classification, the idea was not (as Ranganathan freely admitted). It had its roots in Dewey's device of place (location) as using a standard number (e.g., the United States always being 73) appended to any subject number by means of digits 09, a device now known as a facet indicator. Wynar and Taylor 1992, p. 321 A faceted structure relieves a classification scheme from the procrustean bed of rigid hierarchical and excessively enumerative subdivision that resulted in the fixed 'pigeonholes' for subjects that happened to be known or were foreseen when a system was designed but often left no room for future developments and made no provision for the expression of complex relationships and their subsequent retrieval.