RhymeZone
Search for words that rhyme, synonyms, definitions, and more.Also has dialogue from Shakespeare's plays, grammar quizzes, quotations, famous documents, mother goose, and more.
Acronyms
The World Wide Web Acronym and Abbreviation Server
Thesaurus
Roget's Thesaurus
Style
Elements of Style, by William Strunk, Jr. (1918)
American Society of Indexers
Reference Sources on the Internet
Quotations
Familiar Quotations, by John Bartlett (1901)