- Quizlet Vocabulary Sets. You can search many different topics and study vocabulary words.
- Passport to English. This free website has vocabulary exercises listed by topic.
- Longman Dictionary This is a free online learner dictionary. That means that the defining vocabulary is limited to about 2000 words.
- Cambridge Dictionary Another free online learner dictionary.
- Vocabulary Size. Has a free test to determine approximately how many words you know.
- Academic Word List. Has free exercises for students using the 570 most common words in academic English across disciplines.
- Corpus of American English. (COCA) Lets you search words and collocates to see how they are actually used.