Almanacs
Infoplease: All the Knowledge You Need facts, resources, and activities on a variety of subjects.
Farmer’s Almanac Covers astronomical events, weather conditions and forecasts, recipes, and gardening tips.
GeoHive global statistics, country profiles and regional profiles.
Dictionaries
American Heritage Dictionary of the English Language, 4th ed
Cambridge Dictionary of American English
Dictionary.com
MedTerms medical terminology
Online Etymology Dictionary origins of words
Rhyming Dictionary
Merriam Webster