Meaning of Facet in Library Classification.
A particular aspect of a subject or train of characteristics. E.g., in literature there may be four facets: language, form, author, and work. The term is used chiefly by Ranganathan in the colon classification and explained in detail by B.I. Palmer in his book The Fundamentals of Library Science. Ranganathan defined it as the totality of the sub-classes of a basic class derived by the use of single train of characteristics. So, factors are division of a main class through which all the entries of a class are first grouped under each possible category and then individualized. The facet of class are determined with the help of a certain train of characteristics which are applied to the subject for its division. There are many trains of characteristics each of which divides a subject. A certain number of trains of characteristics will yield an equal number of facets of a class.
It is a concept of 20th century for knowledge classification. It is universally accepted. The credit goes to Ranganathan. All modern researches in documentation, coding, and classification have been influenced by the concept of the facet analysis. Metcalf is not clear in his thoughts as he says, “Facet Analysis seems to mean either what has been called subject analysis of particular documents as a step to their synthetic representation by so-called class or code numbers, or it means the analysis of subject field to discover a basis for its classification, whether enumerative or analytico-synthetic.”
Wildback considered the facets as a synonym of “point of view” according to which subject is divided.