Using Thesaurus is easy. Just select the word in your favorite application and choose "Nisus Thesaurus" from the "Services" sub-menu.
Nisus Thesaurus knows the English language. Using the WordNet lexical reference database, Thesaurus knows over 120,000 words and how they relate to each other. When you lookup a word in Nisus Thesaurus, it will show you related words in six categories. With its built-in dictionary, Thesaurus knows that sometimes the same word means different things. So it will never confuse the related words for "an orange" and "the color orange."