When Google doesn't have the definition you are looking for try the following resources
Middle English Dictionary, a HyperBibliography of Middle English prose and verse, and a Corpus of Middle English Prose and Verse. Also gives access to a large collection of Middle English texts and other resources.
The width and breadth of encylopedias is astouding! From author encyclopedias to thematic ones, the sky is the limit. Check the Library Catalog to see for yourself. Try the search terms (encyclopedias and "topical keyword") such as symbolism, hip-hop, feminism, technology, or New York.