Meaning of Classification:

Systematic grouping of entities (both abstract and concrete) to meet one's requirement is known as classification. Classification lies at the root of all human activities. Our daily life is very much dependent on the process of classification, however, elementary this process may appear. You can surely recall a number of activities around you where classification plays its part. Take, for example, the arrangement of contents in a railway time table, the display of goods in a grocery, shop, the arrangement of modules in a departmental store to facilitate the selection of goods by customers, the seating arrangement in a theatre or stadium, the assignment of registration numbers to various motor vehicles by a state transport authority, or the sorting of letters by postmen first by the city, then by the street and lastly by the house numbers for quick delivery of post.

These are simple examples of how we use classification in our activities. The word classification was derived from the Latin word classes which meant order or rank of mobility in Roman society based upon birth and wealth. Classification is a mental process by which we group or separate things on the basis of common characteristics. For example, things grouped together on the basis of a common characteristic like writing material. In other words, classification is an attempt to identify a class for like things. We succeed in our attempt by applying a characteristic and isolating all like things on that basis from unlike things. Classification in essence means dividing into groups, grouping, sorting, arranging, ordering, ranking and relating one entity to the others. 

S.R. Ranganathan, in his Prolegomena to Library Classification (1967), elaborately discusses the meaning of classification. In the case of physical objects, division and assortment are the two results of classification, According to Ranganathan, while division implies sorting objects into two or more groups, assortment additionally denotes arrangement of these groups in a predetermined sequence. Further, in library classification, the sequence of objects, i.e., documents, is so mechanised by the use of notation that it is reflected in the notation when a document is withdrawn or added.