Dictionaries

• Merriam-Webster
• List of English Online Dictionaries
• yourdictionary.com

Science Dictionaries

• Academic Press Dictionary of Science and Technology
• Life Science Dictionary

Computer and Internet Dictionaries

• Computer and Internet Dictionaries
• High-Tech Dictionary

Legal

• Legal Dictionaries Online

Slang

• The Alternative English Dictionary

Ambrose Bierce

• The Devil's Dictionary