This study assists in solving the problem of formalizing knowledge in manufacturing requirements domain focus in product structure. The first factor that has to be considered to produce the best solution for this problem is by developing ontology to standardize the engineering terms in this domain and annotation to analyze the usage of shared terms between products. The second factor that has to be considered in order to enable the ontology to be reused and extended is by developing ontology development methodology and prepares ontology artifacts that are shareable and publicly available on the World Wide Web (WWW). Finally, the third factor that has to be considered is by developing a searching algorithm in order to apply the ontology in 2D CAD engineering information extraction. This searching algorithm can be used to identify the synonymous term and subsequently helps in complementation and creation of product structure.