DOD Dictionary: US Defence Department master database.
Military Acronyms: An alphabetical database.
Military Acronyms, Initialisms and Abbreviations: Indexed online database of military shorthand terms.
Space and Electronic Warfare Lexicon: Acronyms and terms relating to space, computers, and related technologies. Most terms have source citations.
Tech-Writer.net - Aerial Reconnaissance and Imagery Analysis Acronyms: Mostly military terms.
United States Navy Patrol Squadrons: Glossary of acronyms and terminology.
US Military and State Abbreviations and Acronyms: Contains terms and aircraft designations for all military branches.
USAAF Abbreviations: Glossary of terms used in the United States Army Airforces.