Automatic Synonym Acquisition Based on Matching of Definition Sentences in Multiple Dictionaries

Studies on paraphrasing are important with respect to various research topics such as sentence generation, summarization, and question-answering. We consider the automatic extraction of synonyms (which are a kind of paraphrase) through the matching of word definitions from two dictionaries, and describe a new method for extracting paraphrases. Higher precision was obtained than with a conventional frequency-based method. The new method provided a precision rate of 0.764 for the top 500 data pairs and 0.220 for 500 randomly extracted data pairs when only synonyms were considered a correct answer. It provided a precision rate of 0.974 for the top 500 data pairs and 0.722 for 500 randomly extracted data pairs when hypernyms and similar expressions were also considered correct answers. Our method should be useful for other studies on paraphrase extraction.