According to Nolo's Plain English Law Dictionary (2013), law is defined as "any system of regulations to govern the conduct of the people of an organization, community, society, or nation. A statute, ordinance, or regulation enacted by the legislative branch of a government."
State Law: States can create a variety of laws on issues such as child custody, divorce, landlord-tenant, small business, personal injury, and wills and trusts.
Federal Law: The Federal government creates the law for a few specific subject areas, such as copyrights, patents, bankruptcy, federal taxes, and Social Security
*There can also be areas of the law that covered by both state and federal governments, such as the food and drug regulation.
Courtesy of Nolo's Law for All Website: http://www.nolo.com/legal-research