- Oxford English Dictionary (all ages)
- Definitions, pronunciations, origins, and examples of words in context.
- Grolier Online (all ages)
- A collection of the full versions of many popular encyclopedia.
- Gale Virtual Reference Library (all ages)
- Database of encyclopedias and specialized reference sources for multidisciplinary research.
- Encyclopædia Britannica Online (all ages)
- Contains several Britannica encyclopedias.