504 English Dictionary Words is a free iPhone application developed by Exoplanet Yazilim Ve Danismanlik Hizmetleri Ticaret Limited Sirketi. The app is categorized under Education and Reference, and it aims to help users learn the most common and frequently used 504 English words.

This application offers various features to enhance the user's learning experience. Users can listen to the words and their correct pronunciation, which is especially helpful for non-native English speakers. Additionally, the app provides flashcard, question, and listening games to test the user's knowledge. One of the most significant advantages of this app is that it works 100% offline, which means users can use it anytime, anywhere without an internet connection.