Acronym Finder
Defines over 750,000 acronyms, abbreviations and initialisms from a variety of subjects.
Free Dictionary
The main source of this dictionary is fourth edition of the American Heritage Dictionary of the English Language. There are links to medical, legal and financial dictionaries.
Merriam-Webster Dictionary
Based on the 11th edition of the Merriam Webster's Collegiate Dictionary, published in 2003. Each entry includes a pronunciation, definition, usage and etymology. A thesaurus is also included.
Roget's Thesaurus
The online edition of the 1995 edition, which contains 35,000 synonyms and 250,000 cross-references.
