The process model matching is a critical step in many business process management activities. Process model matching consists of finding correspondences between activities of process models. This article presents a method for matching process model. The proposed method matches (i.e., aligns) two process models in three sequential steps. First, activities in the two process models are extracted. Second, the extracted activities are expanded using synonyms, hypernyms, and hyponyms of its composing words. These synonyms, hypernyms, and hyponyms are extracted from the WordNet thesaurus. Third, the expanded activities are compared using the Monge-Elkan similarity metric to detect matches. An empirical study was conducted on three well known datasets to evaluate the proposed method. The results of the experiment showed that the proposed method has the potential to match business process models in an effective manner when step two of the method is based on synonyms and hypernyms.