Dictionaries provide definition of terms; encyclopedias give a brief overview of a subject.
American Governance (v.1-5) by 
Dictionary of American Government and Politics by 
Encyclopedia of Contemporary American Social Issues (v.1-4) by 
Encyclopedia of Modern Political Thought [electronic resource] by 
Encyclopedia of Western Colonialism since 1450 by 
Hatchet Jobs and Hardball: The Oxford Dictionary of American Political Slang by 
Hyperpolitics: An Interactive Dictionary of Political Science Concepts by 
International Encyclopedia of Political Science [electronic resource] by 
The Oxford International Encyclopedia of Peace by 
Political Theory: An Encyclopedia of Contemporary and Classic Terms by 
The Princeton Encyclopedia of American Political History [electronic resource] by 
The Princeton Encyclopedia of Islamic Political Thought by 
The Wiley-Blackwell Encyclopedia of Social and Political Movements by 
Worldmark Encyclopedia of the Nations by 
