Acronym Finder from Mountain Data Systems - Find definitions of more than 214,000 abbreviations and acronyms.
Dictionary.com from Lexico Publishing Group, LLC - Offers a multi-source dictionary search that includes The American Heritage Dictionary and Webster's Revised Unabridged Dictionary.
MedlinePlus Dictionary of Medical Terms from Merriam-Webster, the National Library of Medicine, and the National Institutes of Health - Online medical dictionary from MedlinePlus.
Merriam-Webster Online from Merriam-Webster - Search Merriam-Webster's online dictionary and/or thesaurus.
OneLook Dictionaries from OneLook - Search more than 675 general and subject dictionaries from this site.
Rhyme Zone from DataMuse - Find rhyming words, homophones, synonyms, and more.
WordReference from Mike Kellogg and WordReference.com - Online French, German, Italian, Russian and Spanish Dictionary. Also includes English definitions