The concept of canon is very broad; in a general sense it refers to being one (adjectival) or a group (noun) of official, authentic or approved rules or laws, particularly ecclesiastical; or group of official, authentic, or approved literary or artistic works, such as the literature of a particular author, of a particular genre, or a particular group of religious scriptural texts, or similarly, one or a body of rules, principles, or standards accepted as axiomatic and universally binding in a religion, or a field of study or art. This can be related to such topics as literary canons, a topic within itself, for which see canon (disambiguation)#Literature.
There is also the concept of the canons of rhetoric, including five key principles, which when grouped together, are the principles set for giving speeches.
^W.C Sayers (1915–1916) established a system of canons of classification Sayers, W.C. (1915-1916). Canons of classification applied to "The subject", "The expansive", "The decimal" and "The Library of Congress" classifications: A study in bibliographical classification method. Lindon: Grafton.
^S. R. Ranganathan developed a theory of facet analysis which he presented as a detailed series of 46 canons, 13 postulates and 22 principles. in Prolegomena to library classification. New York: Asia Publishing House. Spiteri, Louise (1998). A Simplified Model for Facet Analysis: Ranganathan 101. Canadian Journal of Information and Library Science—Revue Canadienne des Sciences de l'Information et de Bibliotheconomie, 23(1-2), 1-30., Retrieved from: http://iainstitute.org/en/learn/research/a_simplified_model_for_facet_analysis.php