The two main law databases, Westlaw UK and Lexis Library both have extensive reference sections and glossaries of legal terms. In Westlaw UK, this is the Insight section and the Index of Legal Terms. Lexis Library has Halsbury's Laws of England and a Glossary section. These can be used to define terms and gain a basic outline of a particular topic.
The Cardiff Index to Legal Abbreviations is essential for finding the correct ways of abbreviating titles of journals and various types of legal documents as required by the OSCOLA referencing system.
Among the other useful reference works are:
The two main law databases, Westlaw UK and Lexis Library are the best sources to find case reports and text of legislation with the most up to date commentary on them. Both have tabs for Cases and Legislation respectively on their home page.
There is an online tutorial on using these resources at: https://canvas.bham.ac.uk/enroll/KYKRAC
Other resources you can use are: