| American Society of Indexers - Thesauri Online Annotated directory. |
| Bartleby.com: Reference Includes "Roget's International Thesaurus of English Words and Phrases" and Houghton-Mifflin's "Roget's II: The New Thesaurus," third edition. |
| HASSET Provides direct term search followed by hierarchical and other types of browsing. Based on a UNESCO thesaurus. |
| Historical Thesaurus of English Contains the vocabulary of English from the earliest written records to the present, with known recorded dates of usage, taken from the Oxford English Dictionary. |
| Lexical Freenet Search for relationships between words and concepts that might never have occurred to you before. |
| Online Thesaurus Find synonyms using this free online thesaurus from AOL's Research and Learn channel. |
| Phrases Thesaurus A resource for writers. Enter a single word and it will return a list of phrases and sayings that are related to the word in some way. In English. |
| Roget's Interactive Thesaurus Roget's Thesaurus of English words and phrases. |
| Roget's Thesaurus - As distributed by Project Gutenberg E-text of Roget's Thesaurus No. Two, which is derived from the version of Roget's Thesaurus published in 1911. |