Wex is from Cornell's LII project, which features articles and definitions from legal experts. Browsing all entries alphabetically or a standard search are the main page's options. You can browse by article topic via a separate page as well.
This free legal encyclopedia is from Nolo, a site that also offers paid content in the forms of books and software.
Summaries of different areas of laws generally (or "practice areas"). Within these guides, there are more narrowed down articles as well as state-specific guides.
Explanations of different areas of law, usually common claims. Some areas will include more resources such as 50-state-surveys.
A collection of open access monographs. The database as a whole features many different topics of books in many different languages, but here is a filtered result for law books in English.
Free version of Black's Law Dictionary, but is the 2d edition (whereas Westlaw currently features the 11th edition)
A list of common legal terms provided by the American Bar Association that can be navigated by letter. No search function but using "CTRL+F" on most browsers will allow you to search the page for terms or definitions.
Browsable by letter or free search terms with provided suggestions. This dictionary will give examples for how the term may be used.
Can browse terms and search by term or by definition.