**3.2 Properties**

The ontology has two types of properties: the first type is an attribute of a concept, and the second type is a relation between two concepts. An attribute is a property that a concept own as an important part or feature. For example, name is one of typical attributes of a human, while parent and child relationship is one of typical relations on humans.

We often describe a property by the ⟨name of a property⟩.
