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Exercise 3: Add a Comment Annotation to Your Ontology 
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1. Make sure you are in the Active Ontology tab. In the view just below the Ontology IRI and Ontology 
Version IRI fields find the Annotations option and click on the + sign. This will bring up a menu to create 
a new annotation on the ontology.  
2. The rdfs:comment annotation should be highlighted by default. If it isn’t highlighted click on it. Then 
type a new comment into the view to the right. Something like A tutorial ontology for the Pizza domain.  
3. Click OK. Your Active Ontology tab should like Figure 4.3.   
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Figure 4.4: The Class Hierarchy View Options 
 
 
4.1 Named Classes 
The main building blocks of an OWL ontology are classes. In Protégé 5, editing of classes can be done in 
the Entities tab. The Entities tab has a number of sub-tabs. When you select it, the default should be the 
Class hierarchy view as shown in Figure 4.5.4 All empty ontologies contains one class called owl:Thing. 
OWL classes are sets of individuals. The class owl:Thing is the class that represents the set containing 
all individuals. Because of this all classes are subclasses of owl:Thing.  
 
 
 
 
4 Each of the sub-tabs in the Entities tab also exists as its own major tab. In the tutorial we will refer to tabs like the 
Class hierarchy tab or Object properties tab and it is up to the user whether to access them from the Entities tab or 
to create them as independent tabs.  
Add Subclass 
Add Sibling Class 
Delete Class