When I visited a website, there were some vocabularies that I didn't know what they mean. I looked up the dictionary to see their meanings. At that moment, there was one thing coming into my mind. How can I know if I should memorize those vocabularies or not? If those vocabularies are popular in the TOEFL, IELTS, etc., I should definitely memorize them. As the result, I built this tool to see if I should memorize those vocabularies or not.