Learner-focused dictionaries and pronunciation tools with clear definitions, example sentences, collocations and audio.

dictionary.cambridge.org
Clear learner-friendly definitions, example sentences and audio pronunciation with a strong ESL focus.
oxfordlearnersdictionaries.com
Definitions written for learners, with word lists, collocations and audio in British and American English.

merriam-webster.com
A comprehensive American English dictionary and thesaurus with clear usage notes.
ldoceonline.com
Learner definitions, collocations and the Academic Word List from Longman, with clear examples.

collinsdictionary.com
Definitions, example sentences and word-frequency information aimed at learners of English.

youglish.com
Hear how any word or phrase is really pronounced, using thousands of real YouTube clips.