Reading a broad summary will help you understand your topic and see how it relates to broader, narrower, and related issues. It is also a great source for finding terms of art commonly used for your topic. These keywords should be used to help you further your research.
Nolo's Plain English Law Dictionary, ALM's Legal Dictionary, Grapeville, LLC.'s Black's Law Dictionary 2nd edition, and FindLaw Legal Dictionary are free on the web, mobile web sites, or in app stores. Thomson Reuters sells apps for the current version of Black's Law Dictionary and Osborn's Concise Law Dictionary. Wolters Kluwer sells an app for the Bouvier Law Dictionary, Compact Edition.