WordSurf

WordSurf is a special reference tool with 120,000 root words, that combines the features of a dictionary, a thesaurus, and much more.

In addition to providing definitions, synonyms and antonyms as you would find in standard references, WordSurf allows you to ask questions that no standard reference can answer, such as "what are the parts of an automobile?" or "what musical instruments are similar to a guitar?" or "what animals are mammals?"