The Oxford Advanced Learner's Dictionary (OALD) app is written for learners of the language with such features as the Oxford 3,000 (the most important words to know in English), more than 185,000 words, phrases and meanings and Full Text Search to find your word in any idiom, phrasal verb or example sentence in the dictionary. Integration with Office 365 means it can be used in a familiar environment.
"OALD contains all the extra information about the words that students need to succeed in learning English," says Paul Keyworth of St. Cloud State University in Minnesota.
For more information on the Oxford Advanced Learner's Dictionary and Oxford University Press, read the datasheet.