Defines mathematical words and concepts, and indicates the links between them.

Enter a single word and it will return a list of phrases and sayings that are related to the word in some way.

Contains 35,000 synonyms, succinct word definitions and a hyperlinked category index.

85,000 hyperlinked cross-references, plus proverbs and quotations from classic and modern authors.

Searchable online version of Roget's Thesaurus of English words and phrases.

A dictionary and thesaurus in one. Also gives parts of speech and examples for more than 50,000 words.

Searchable online thesaurus from Merriam-Webster.