The Vocabulary.com Top 1000
The top 1,000 vocabulary words have been carefully chosen to represent difficult but common words that appear in everyday academic and business writing. These words are also the most likely to appear on the SAT, ACT, GRE, and ToEFL.
To create this list, we started with the words that give our users the most trouble and then ranked them by how frequently they appear in our corpus of billions of words from edited sources. If you only have time to study one list of words, this is the list.