= Individual or instance

= Class or concept

Basic OWL terminology 1/2

Classes may have subclasses (superclasses)

Example - Classes: people, dog, terrier Individuals: Bob, Brandy

“Terrier” is a subclass of “dog”

D R

Basic OWL terminology 1/2

Classes are defined by their properties.

Datatype property: A feature or attribute. E.g. people have age.

The value of the property is a number or string: Bob is “17”.

Object property: A relation between two classes, called domain (D) and range (R) of the property. E.g. dogs are fed by people.

The value of the property is an individual: Brandy (a dog, instance of class

“terrier”) is fed by Bob (a person, instance of class “People”).

Note that...

•... there is no clear rule for deciding whether something is a class, a property value or an instance

•...there is no one single correct way for building an ontology

•...ontology development is iterative