The New Macmillan American Dictionary, developed by Study Center, is a comprehensive dictionary for American English learners. It sets the standard of excellence for lexicography with the most comprehensive and accurate coverage of American English available. With over 100,000 references and 80,000 examples of words in use, it has more references than any other English learners' dictionary.

The dictionary features only 2,500 words used to define all entries, and it provides up-to-date information on new words, spoken English, and changes in meaning. The definitions are short and clear, with menus in longer entries to help find the meaning quickly. The application also includes additional collocations, synonyms, and word origins for a more comprehensive learning experience.

Furthermore, the New Macmillan American Dictionary provides a guide on how to use the dictionary, and it allows you to search using wildcards and suggested words. The predictive text in search helps you with spelling as you look for words, and it enables you to search for idioms and phrasal verbs. You can also create group vocabulary, and the search history helps you find recently searched for words. The application supports search from within other compatible apps on your device, and you can bookmark your favorite words for future reference.