The major legal encyclopedia is Halsbury's Laws of England, shelved at Law Reports and Legislation SE20. This is a good place to start to find the law on a particular topic.
You can also find it online on LexisLibrary - use the Commentary tab to access it.
You can also find basic legal information in Oxford Reference Online
American dictionary also available on Westlaw. Click Services - International materials - Thomson Reuters Westlaw (top left) - Secondary sources- Tools and resources on right - to access it.