To know what is ontology clearly and how to build ontology, i use daycare ontology from and try to figure out step by step based on [1] and [2]. Ontology is developed in protege 3.2. This is my summary; Ontology Building . It is about how to build ontology step by step with daycare.

Reference :

[1] N.F Noy, and D.L. McGuinnes, Ontology Development 101 : A Guide to Creating Your First Ontology, 2001

[2] Horridge, Mattahew, A Practical Guide to Building OWL Ontologies Using The Protege-OWL plugin and CO-ODE Tool, The University of Manchester, 2004