Categorization is the process in which ideas and objects are recognized, differentiated, and understood. Categorization implies that objects are grouped into categories, usually for some specific purpose. Ideally, a category illuminates a relationship between the subjects and objects of knowledge. Categorization is fundamental in language, prediction, inference, decision making and in all kinds of environmental interaction. It is indicated that categorization plays a major role in computer programming. There are many categorization theories and techniques. In a broader historical view, however, three general approaches to categorization may be identified: Classical categorization Conceptual clustering Prototype theory