One of the method of context modeling is by using ontologies. Ontologies facilitate structuring data and representing knowledge. It define a given domain in a graph structure which contains concepts present in the modelled domain, the relationship between concepts and potentially classification axioms which specify generic knowledge about the domain. The ontologies is exploited by means of reasoning mechanism to reflect the semantic of the data, and thus the information and the knowledge. Further, reasoning can also be used to detect inconsistencies in the model as well as infer new information out of the correlation of the data. The most used and well known language to describe ontologies is OWL web ontology language (OWL).