This paper presents a new semantic relatedness measure on ontologies which considers especially the object properties between the concepts. Our approach relies on two hypotheses. Firstly, using only concept hierarchy and object properties, only a few paths can be considered as “semantically corrects” and these paths obey to a given set of rules. Secondly, following a given edge in a path has a cost (represented as a weight), which depends on its type (is-a, part-of, etc.), its context in the ontology and its position in this path. We propose an evaluation of our measure on the lexical base WordNet using part-of relation with two different benchmarks. We show that, in this context, our measure outperforms the classical semantic measures.