A grouping of related goods or services based on similar characteristics. For example, packaging as a category may include a variety of different goods and materials, all of which share a common purpose. Each category may be further divided into sub-categories based on physical characteristics, such as plastic packaging, or cardboard packaging. Categories are often part of a hierarchy of classification, sometimes called taxonomy, though one of the most widely used, the UNSPSC does not use the term category. See also UNSPSC.