New and revised entries added each quarter. A dictionary of the English language containing 450,000 vocabulary entries. The Merriam-Webster Dictionary and Thesaurus, online and searchable. Please Dictionary Provides 125,000 entries.
Links are unannotated but numerous.
Internet Public Library - Dictionaries Reference IPL's annotated directory of dictionary sites. The Human-Languages Page Dictionaries and other resources for many different languages. Dictionaries and Translators A great number of dictionaries, including translators in almost every language. Gives English definitions and pronunciations. Thesaurus A searchable hypertext version of Roget's Thesaurus.