Oxford Advanced Learner’s Dictionary 9th Edition (for Bluedict and MDict)

The Oxford Advanced Learner's Dictionary, or OALD, is recommended by teachers and students because it defines words in language students understand, gives useful example sentences, and includes the tools learners need to succeed in English.

The 9th Edition includes 145,000 words, phrases, and meanings and 85,500 examples showing how to use words. British/American English pronunciation at every entry, with a written transcription and accompanying audio. For maximum learning and user engaging there is expand vocabulary feature available that help users to use the color illustrations and usage notes to explore related words and phrases. 

Just like many other third-party apps, BlueDict is only a database "reader". So you need to get the databases (.MDX / .MDD / .CSS files) then put them into /sdcard/BlueDict/Dicts or your specified path.