Several of these resources are restricted to University of Michigan users. You may be prompted for your uniqname and password in order to access some resources.
Both Hatcher and Shapiro libraries have rich collections of subject-specific encyclopedias on almost any topic.
One way to search for them in Library Catalog Search is to use the topic as a keyword search: e.g., "encyclopedia of medieval women" ; results will bring up Women and gender in medieval Europe : an encyclopedia / Margaret Schaus, editor as a hit.
When that doesn't work, try an advanced Library Catalog Search using "encyclopedias OR dictionaries" as a SUBJECT term and your topic as an keyword term. Not all historical dictionaries will have "encyclopedia" in their title, so this will increase the likelihood that you will find a relevant source.
For example:
All Fields: europ* politic*
Subject: encyclopedias OR dictionaries
[Note: the * at the end of europ is a wildcard, which means that the search will result in alternate endings of the word (e.g., europe or european).]