90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.
The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.
When the mythical Greek hero Achilles was a baby his mother dipped him in the River Styx to protect him from all injuries. But she held him by one heel which therefore was not protected. He was eventually killed by an arrow that hit his heel.