In Chapter 5 we discussed different types of semantic relationships and contrasted abstract relationships between categories that define a semantic hierarchy like
Meat → is-a → Food
with concrete relationships involving specific people like members of the Simpson family:
Homer Simpson → is-a → Husband
When we make an assertion that a particular instance like Homer Simpson is a member of class, we are classifying the instance.
Classification, the systematic assignment of resources to intentional categories, is the focus of this chapter. In Chapter 6, “Categorization: Describing Resource Classes and Types”, we described categories as cognitive and linguistic models for applying prior knowledge and we discussed a set of principles for creating categories and category systems. We explained how cultural categories serve as the foundations upon which individual and institutional categories are based. Institutional categories are most often created in abstract and information-intensive domains where unambiguous and precise categories enable classification to be purposeful and principled.
A system of categories and its attendant rules or access methods is typically called a classification scheme