Answer: It is the study of city, government, politics, liberty, justice, property, rights, law, and the enforcement of a legal code by authority. It's focus regarding these social aspects is to understand - what they are, why (or even if) they are needed, what makes a government legitimate, what rights and freedoms it should protect and why, what form it should take and why, what the law is, and what duties citizens owe to a legitimate government, if any, and when it may be legitimately overthrown - if ever.
Next Question: What is Aesthetics?
Previous Question: What are Ethics?