Merriam

Get America's most useful and respected dictionary, optimized for your iPhone, iPad, and Apple Watch. Continuously updated with the newest words and meanings, this is the premier iOS app for English language reference, education, and vocabulary building.
Key Features:
* No ads!
* Premium Content: Over 15,000 additional entries covering people and places
* Offline access: Complete access to definitions and synonyms whether or not you're connected
* Voice Search: look up a word without having to spell it
* Word of the Day: learn a new word every day
* Word Games: fun, fast quizzes to test your vocabulary
* Favorite Words and Search History: keep track of the words that are most important to you
* Favorite Word Syncing Through iCloud: share your favorites between devices and on the Web
* For Tablets: browse the entire dictionary with a scrolling index
* Apple Watch Extension: see the Word of the Day and find watch-sized definitions with voice search
Expert Word Guidance:

* Integrated Thesaurus: more than 200,000 word choices with examples of their use
* Example Sentences: understand how a word is used in context
* Audio Pronunciations: voiced by real English speakers, not text-to-speech robots

Terms of Use: https://www.merriam-webster.com/terms-of-use