Topical Dictionary is an application to make it easy to create dictionaries with selected words. It has more than 400 thousand words with descriptions, examples, and more.
The purpose of the application is while reading, researching, or watching movies in English. Noting the words you dont really know the description and after a while check the list to study and expand vocabulary easily.
Using Topical Dictionary is better than using a pen and paper or a standard note-taking application because it is built for this specific purpose.